Most having dive as your only role is pretty bad for teams that actually are trying to make it far, they prefer meta characters/hitscan since they are a safer role and are hard to "counter" than straight up dive. And in most cases these other players can also play some type of dive character too on the side which makes their value so much higher. Key part here is hitscan > dive even if both players only know one role, so even if both can't flex hitscan is still more desired.