True but the same number of opponents can be beaten in matches. A single game is still a single game, even against a lot of opponents. Actually it's not possible to make so many matches but it's very unbalanced in favor of tournament achievements right now.
20 years peak range
#1 | Garry Kasparov | 2856 | |
#2 | Anatoly Karpov | 2818 | |
#3 | Emanuel Lasker | 2809 | |
#4 | Alexander Alekhine | 2781 | |
#5 | Viktor Korchnoi | 2766 | |
#6 | Vassily Smyslov | 2759 | |
#7 | Paul Keres | 2755 |
"The reason why some players got beaten bad in matches despite their high rating, is because some of them were more of a tournament player, and since matches between players are not organized as frequently as the number of tournaments, the rating system can not give a reasonable assesment of player's strength"
I'm not sure if I think there are tournament and match players, and that it is matches that show the players strength. I think the rating system is doing a fairly good job, then one can overestimate it just as well as one can overestimate a match result, but at least the ratings are based on all games against all opponents, so they can't get it all that wrong in the end.