Another possible reason YouTube may fall is death by a thousand cuts. There used to be three TV channels available to most of the USA. Then there were 300+ many less people tuned into the big three channels and the only reason they are still in business is because they own a chunk of those channels.

YouTube has a hole in its (political) right flank. It doesn't compensate creators left, right or center when they vlog about controversial topics. Further by banning or not paying creators it spawns the existence of tools like Rokfin. Its a speck on YouTube's wall now but if the platform becomes more strict it may see a loss of market share.