The majority of people play at least some competitive games and most of those simply don't work due to anticheats. These game usually are also the most important ones to them.
Steam currently has 35M peak daily active users. Out of the top 10 Games by player count only 2 dont work on proton: Pubg and CoD, those two together have a daily peak of 0.7M players. At number 11 you are already down to 0.07M daily peak.
I think your definition of "most" leaves something to be desired.
The majority of people play at least some competitive games and most of those simply don't work due to anticheats. These game usually are also the most important ones to them.
Steam currently has 35M peak daily active users. Out of the top 10 Games by player count only 2 dont work on proton: Pubg and CoD, those two together have a daily peak of 0.7M players. At number 11 you are already down to 0.07M daily peak.
I think your definition of "most" leaves something to be desired.