Isn't this what they are optimizing for though? I don't work at Google so I don't know and I block ads so I am not engaging with their revenue generation (at least in the most direct sense) but the idea seems to be if you are watching X content you then want to see more of X and it drives total engagement time. I think it sucks and is part of general trend of not being able to find diverse and cool content on the web..but hey Google