This is technically true, but in most team based multiplayer games you actually get much shorter focus intervals due to breaks and pauses like dying (time to respawn or end of round, which can take up to multiple minutes) or running to the action from spawn (games like Overwatch).

Also the team aspect hides much of it so a lot of players go "on autopilot" too in these games, you have to keep in mind that the far majority of players in the super popular games plays at a lower level.

Compared to this a game like Starcraft 2 (1on1 competitive) actually requires uninterrupted focus for a full game with basically no breaks or pauses, but 1v1 competitive multiplayer games are not as popular as team based games.