quick question about tf2

tf2 has been and still is really popular, but not by player count, by content, memes and ideas. many videos were about tf2, tf2 references in games and memes, tf2 memes and references are literally in so many games, and since tf2 is this popular in content and memes, why is it not so popular in player count? the highest amount tf2 had was in 2023, when they only had 250 active players and be honest, everyone atleast played tf2 back in the day but the player count is low for all these years, what is going on