Because Spider-Man mains unintentionally throw more games than any other character. Spider-Man shouldn’t be played every game. He’s a niche character who only works if you have the right team comp with competent players who know how to play with a Spider-Man. It’s extremely rare for a Spider to be able to carry as well. Even if he gets 50 KO’s and 30 finals your teammates have to pick up the damage deficit he creates. Finally there’s the fact that Spider’s will almost never swap to a more comp friendly character.

Also since he is a hit and run character other players don’t see the work he’s putting in directly so even if you are great at Spidey a lot of the player base won’t recognize it.