Frankly, I disagree that 4chan's decline had anything to do with politics. Rather, it was caused by the internet's uncanny ability to turn any discussion into meaningless shitposting. All the /pol/ vs /anyoneelse/ shit-flinging is just a fight between native and cross-board shitposters, and not different from those of yore (back when it was /b/ and /v/ flinging shit).

Your board choice and use of "meme" as a verb tells me you were part of the problem.