Because of his “edgy”, shitty provocative humour and how high profile he was, he’s generally considered one of the horsemen of the adpocalypse.

He did one too many nazi joke, articles were written, and suddenly all content creators had it a lot harder to get ad revenue, because announcers were all like “associating with youtube creators will ruin our brand”.

Pewdiepie may not be the only factor, but he was certainly a big one.