I find the bigger problem with online comments are that people repeat the same comments and "jokes" over and over and over again. Sure we had those with YouTube 15 years ago when people always spammed "first!" and "who is listening in <year>?" but now it's gotten worse and every single comment is now just some meme (especially on Reddit) or some kind of "gotcha"...
Not exactly, bot farms can still be made with poor people IDs through black market. I don't know what the solution is going to be, but at some point we might forced to accept the reality that on the internet humans and AI won't be distinguishable anymore and adjust our services independently on the client being a person or a machine.