I don't think Fischer would have been able to just play title matches in 1975, 1978, 1981 and 1984, even less winning the last two of them against Karpov or Kasparov. It was very hard to make him play one single match against Spassky and impossible to make him play one against Karpov. He was losing contact with reality already early in the 1970s. Larry Christiansen met Fischer in 1978 and just felt sorry for him, he kept talking about the Jews and their world conspiracies and had no respect for the way Karpov played chess. It might have been a rude awakening for him if he still had been able to play someone like Karpov, a much stronger player than Spassky and still improving throughout the 1970s.
Fischer vs Karpov '75 and the future of chess...

We don't really need to do counterfactual history on the '75 match. Fischer wasn't prevented by anyone to defend the title, he pondered the situation and decided he was better off not showing up. Karpov wins.
*Waits raul72 / Reb chiming in*

Possibility 1 ... opponent is Spassky, Fischer accepts and plays
Possibility 2 ... Korchnoi, Fischer had a bad record but plays and wins
1975, Fischer vs Korchnoi, 1-0
1978 Karpov vs Fischer 0-1
1981 Karpov vs Fischer 1-0
1984 Karpov vs Kasparov 1-0
1985? Karpov vs Kasparov 1-0
1988 Karparov etc
possibilty 3: Karpov seen to outplay the competition, including Korchnoi, nervous Fischer won't play on normal terms - or
possibility 4: Fischer has nothing to prove, no longer has passion for competition, his games vs the computer Greenblatt have proven to him that chess is no longer worthy of his time, resigns to the winner of the playoffs.

We don't really need to do counterfactual history on the '75 match. Fischer wasn't prevented by anyone to defend the title, he pondered the situation and decided he was better off not showing up. Karpov wins.
*Waits raul72 / Reb chiming in*
Those who don't learn from history's mistakes are doomed to repeat them -cough, carlsen, cough, ahemagnus- Sorry had to clear my throat.
We can't change the past, but the future youngsters can learn and see how their legacies can be tarnished or made supreme by seemingly routine games/matches/tournaments, even if they are technically dominant for several years over the current crop of super-GM's (which no one can claim now).

The only scenario---During the 75' match every GM in Russia and many GMs throughout the world will be checking Fischers every move in the match for errors. The Russians will do anything and everything to stop Fischer. They do everything they can to prevent Fischer from showing up---and they succeed! Once Karpov is enthroned they restore the return match clause (which was refused to Fischer). And now Karpov and Kasparov can play for the championship, to the point of nausea, for the next decade---which they do!
Kasparov, because of greed, breaks away from fide, and screws up chess even more. which brings us up to today when everyone is asking---when is Kasparov gonna have a legitimate simul??
I just want to call your attention to that famous movie about Bobby when he calls Karpov a no good commie cheater---And the Russians shoot Bobby in the back. As he is riding away (mortally wounded) a boy runs along behind Bobby's horse.
"Bobby wait" Dont go Bobby, there is blood on your shirt.
I'm OK Joey.
Bobby, he would never have been able to shoot you if you'd seen him.
Bye little Joe
He would never have been able to clear his holster, would he Bobby
as Bobby rides off into the twilight little Joey shouts into the darkness
Bobby, Bobby, come back Bobby! Bye Bobby!
The mountains echo Joey's plaintive call as Bobby (slightly slumped over in his saddle, wounded and dying - or already dead?) rides up the crest of Cemetery Hill through the tombstones and ascends toward the snow-capped Tetons.
Do you remember that great movie?

more likely the Russians had simply allowed Fischer to take the championship because he complained about the fixed draws or at least thats what he suspected. As he had just been given the championship on a platter he decided that he was clearly the biggest cheat of them all and resigned.

more likely the Russians had simply allowed Fischer to take the championship because he complained about the fixed draws or at least thats what he suspected. As he had just been given the championship on a platter he decided that he was clearly the biggest cheat of them all and resigned.
The Rest of the Story---
Not so much anymore but there was a time when chess was king in Russia. Nothing stopped people from playing---not WWII when the Moscow chess championship was being played while German guns shelled the city. Sickness couldn't stop them---Tal would sneak out of hospitals to go play at local clubs. Chess was a way of life in Russia and they lived for the championship. The chess hierarchy demanded they win the championship---by hook, or by crook. They would either cheat or they wouldnt eat.
And thats the rest of the story!

So 1975, Karpov wins by the cheating commie machine possibly...
1978 and 1981 Kasparov is still too young...would Bobby come back Chuck Norris/Delta Force style to reclaim his throne (insofar as any human can be like Chuck Norris...just being hypothetical, even though we all know strictly this is not even remotely possible)?

Chess was invented by chimpanzees who had wandered into a desert with nothing to do but play with rocks, probably, amusingly, they started by attacking ants.
We don't really need to do counterfactual history on the '75 match. Fischer wasn't prevented by anyone to defend the title, he pondered the situation and decided he was better off not showing up. Karpov wins.
*Waits raul72 / Reb chiming in*
Those who don't learn from history's mistakes are doomed to repeat them -cough, carlsen, cough, ahemagnus- Sorry had to clear my throat.
Some similarities but also some differences. Fischer stopped playing in 1972 while Carlsen is playing the strongest opponents in all events except the Candidates. It's probably a mistake if what matters most to him is his position in chess history. Most people would count five 3000+ performances in Nanjing or repeated Wijk wins ahead of Anand and Kramnik as saying much less about his place in chess history than his winning a couple of blitz tiebreaks in Kazan against Radjabov and Kamsky, if the latter would get him a title match. Anyway, Carlsen is only 20 and Fischer played a couple of Candidates already 10-12 years before 1971-72. Anand didn't play for the real World Championship between 1995 and 2007, if he had done that I doubt that Kramnik ever would have won the title while Anand could have held it for over a dozen years. Now he declined participating for a long time but is still one of the greatest, so Carlsen could still win the title if he gets more interested in participating.

People misunderstand Fischer's strengths. The flashy tactics were always the result of a clear positional advantage. He exploited the opponents' weaknesses with ruthless precision. He was also deadly with the initiative, he had a knack for pressing it with every move.
Karpov was Fischer's nightmare opponent. Even as a young GM, Karpov refused to create weaknesses in his position and never missed the tactics. He would already be a slight favorite over Fischer in 1975; by 1978 he was dominant over the whole world except for Korchnoi - who had a lifetime plus record against Fischer.
Even in his matches against Kasparov, it was only uncharacteristic blunders no GM would normally make which tilted the results. Kasparov's great genius won, and earns him the all-time-greatest title, but he never dominated Karpov.
Karpov also holds the all-time record for master tournament wins at 120. Second is Kasparov with 63, and no one else is close to either of them. Karpov was an active competitor his entire career - you needn't look past the next super tournament to find him.
Sorry, I wont let this one slide..... its easy to verify that Korchnoi and Fischer were dead even against one another , Korchnoi did NOT have a plus against Fischer.
http://www.chessgames.com/perl/ezsearch.pl?search=Fischer-Korchnoi

Karpov also holds the all-time record for master tournament wins at 120. Second is Kasparov with 63, and no one else is close to either of them. Karpov was an active competitor his entire career - you needn't look past the next super tournament to find him.
Wow that's a surprising statistic. What do you mean, exactly, by "master tournament wins"? I find it hard to believe that lasker didn't have more than 63. Are you discounting match play, meaning literally only tournament play in this statistic?

If Anand, Carlsen and Aronian could all go back in time to play Fischer in a 10 game match, I bet they would all score at least 5 points each against him assuming they were all in the peak of their chess career (eg. you don't get a 20 year old Fischer against a 15 year old Carlsen).

People misunderstand Fischer's strengths. The flashy tactics were always the result of a clear positional advantage. He exploited the opponents' weaknesses with ruthless precision. He was also deadly with the initiative, he had a knack for pressing it with every move.
Karpov was Fischer's nightmare opponent. Even as a young GM, Karpov refused to create weaknesses in his position and never missed the tactics. He would already be a slight favorite over Fischer in 1975; by 1978 he was dominant over the whole world except for Korchnoi - who had a lifetime plus record against Fischer.
Even in his matches against Kasparov, it was only uncharacteristic blunders no GM would normally make which tilted the results. Kasparov's great genius won, and earns him the all-time-greatest title, but he never dominated Karpov.
Karpov also holds the all-time record for master tournament wins at 120. Second is Kasparov with 63, and no one else is close to either of them. Karpov was an active competitor his entire career - you needn't look past the next super tournament to find him.
Sorry, I wont let this one slide..... its easy to verify that Korchnoi and Fischer were dead even against one another , Korchnoi did NOT have a plus against Fischer.
http://www.chessgames.com/perl/ezsearch.pl?search=Fischer-Korchnoi
Sorry, but I cant let this one slide either. Does anyone in their right mind think Korchnoi was fischer's equal? I thought it was well known that when Fischer was blazing through the candidates ---the Russian heirarchy asked Petrosian and Korchnoi who could beat Fischer. Korchnoi said "not me". Petrosian said "I think I can take that guy". And they paid Korchnoi off and he let Petrosian win their candidates match and go on to play Fischer. Its in the book---look it up.
Karpov's 120 tournament wins, yeah you can chalk that up to Fischer too. Karpov backed into the title and to prove he was worthy he played anywhere and everywhere. He never completely overcame the fact that he was the only champion to gain the title without playing.
It was a monumental task for Karpov to overcome the aging Korchnoi in the 78' match. Karpov was 25 and Korchnoi was 47. If Korchnoi put up such a magnificent fight---what would the Fischer king have done. Man, its not pretty to even think about it!
Karpov also holds the all-time record for master tournament wins at 120. Second is Kasparov with 63, and no one else is close to either of them. Karpov was an active competitor his entire career - you needn't look past the next super tournament to find him.
Wow that's a surprising statistic. What do you mean, exactly, by "master tournament wins"? I find it hard to believe that lasker didn't have more than 63. Are you discounting match play, meaning literally only tournament play in this statistic?
Karpov was a great player but I think those stats are partly explained by his playing many rather weak events, at least compared to Kasparov. Karpov didn't win 6 top events 20 years in a row or something like that, but he is often underestimated.
My scenario based on my skills in visualizing alternative nonexistent universes (can't remember what the judge or psychiatrist called this)...
1975: Fischer over Karpov
1978: Karpov barely over Fischer (Fischer subconsciously lax about Karpov's abilities)
1981: angry vengeful obsessive Fischer over Karpov
1984: Fischer barely over Karpov or Kasparov because they revealed their best plans in their grueling candidates match.
Fischer retires, goes nuts, whatever.
Karpov and Kasparov still with a decade of epic battles and maybe this time no PCA getting in the way, maybe Kasparov still playing to this day.