Gamergate was never an organized business model, Comicsgate is. GG was a bunch of people - rightly - getting pissed off and calling out bullshit and, outside of occasionally organizing some campaigns, didn't go much beyond that.

CG was a bunch of people - rightly - getting pissed off, and deciding to sell their own stuff to compete with the bullshit. Totally different models, one of which is a lot more sustainable because it has direction and purpose built right into it. Not saying this in a bad way, but CG exists to make people money; they're going to do everything they can to keep their livelihoods. Fewer people built their livelihoods on GG, and those that did did so in such a way that it was transferable to any other internet venture, basically. They built their online personality/name as their brand, and could basically do anything with that. For the biggest people, GG served its purpose, and there wasn't as much incentive to keep driving it forward. And, as someone else mentioned, some of those people even got TDS and other lib-related issues, and ended up actively hating the movement they either helped build or latch on to. So, in some ways, the falling in relevance of GG was active sabotage by a bunch of bitter weirdos.

But I think the bigger issue is the first one I mentioned; CG is a business model, GG never really was.