Spassky only actually won two games, including the famous first game Fischer blunder loss, and drew 11 games.
Karpov thrashed Spassky in training match for WCh!

The supposed training match did not happen.
This, from an interview by Irwin W Fisk:
Irwin Fisk: When did you first become aware of Bobby Fischer?
Anatoly Karpov: People started to talk about Fischer, but I was living very far from Moscow at that time and we had no Internet, no TV, so information was slow in coming. But, of course after the Candidates Match everyone knew Fischer.
IWF: How old were you in 1971?
AK: I was 20 years old. I was already one of the strongest grandmasters.
IWF: Spassky was in preparation to play Fischer for the World Championship. Had you played Spassky?
AK: Yes, I played a training match with Spassky. He asked me to play training games, but we played only one game. Spassky won this game even though he had a lost position, but I made a stupid mistake, and after this suddenly Spassky said he didn’t want to continue this training match, so maybe he was happy he beat me in that game.
IWF: Where was this game played?
AK: We were near Moscow.
IWF: Was it at a training facility?
AK: Spassky had a training session before he left for Reykjavik. He had some problems in putting together his team and making last minute preparations, so he wasn’t concentrating so much on chess. I stayed at the training session two weeks, and almost every day Spassky was going to Moscow and coming back. It was near Moscow, like 60 km from Moscow, but he had to go to the city every day, so you can’t concentrate. We were analyzing a lot. [Efim] Geller was there. Then, [Nikolai] Krogius was there, then Iivo Nei, so that was his team. Reykjavik was soon, and I was there, but the main piece [Spassky] was not there. Spassky only came in the evenings, and as I said it was not very serious what he had done.
According to Frank Brady's Bobby Fischer: Profile of a Prodigy (p.218) after the Alekhine Memorial Tournament in November/December 1971, won by Karpov, Spassky played a 24-game "training match" against Karpov. Thus the match was the same number of games as the World Championship.
Apparently Spassky lost this match 6-18!!
Karpov thus beat Spassky by a much bigger margin than Fischer beat Spassky in 1972.
By 1975, Karpov would have been even stronger.
Who *doesn't* think Karpov could have beaten Fischer in 1975?
Yes, Brady talks about that and other "stories". I certainly dont believe Karpov , nor anyone else, could beat Spassky by a +12 score ! Thats simply ridiculous.
It's not really that ridiculous.
Karpov was miles ahead of Spassky in the 70's.
ChessGames.
Classical games: Anatoly Karpov beat Boris Spassky 14 to 2, with 23 draws
In their Canditates Semifinal Karpov wons four games to Spassky's one out of 11 games. The rest were drawn.
What's ridicilous is that you would question a Frank Brady, a highly respected man.
It is a shame Karpov never got to prove he was better then Fischer. I believe Karpov was much stronger then Spassky by the time he was ready for the title. Without a doubt Karpov is underestimated by so many people in my opinion. I believe he was capable of beating Fischer, which might be reason Fischer never gave him the chance to prove that in 92 as well.
And Fischer wasn't? If you omit the one forfeit and the one joke game (or don't omit the first game, but it does seem bizarre) Spassky really lost 6 and a half to 12 and a half.