Simon: He's also incapable of building a sustainable business.
The thing is, he was on the way to building one. He had a concept, that concept (reaction/commentary videos) is (inexplicably, IMO) popular on YouTube, he had a staff that was doing most of the work and letting him focus on the parts he wanted to do. The challenge would have been adapting and finding other topics in order to increase his viewership. Not a guarantee, but at least the foundation was there.
There are YouTube creators making a small (and not-so-small) fortune doing that. Evans at least had the possibility of growing the channel into something quite lucrative by not being a selfish pig of a human being. In other words, he ruined it by being unable to clear the lowest rung on the ladder.