Sorry, should have been more clear. My bad. What I meant was if an algorithm had to "choose" between _trying_ to maximize views over all videos over all users,

Sorry, should have been more clear. My bad. What I meant was if an algorithm had to "choose" between _trying_ to maximize views over all videos over all users, and _trying_ to maximize niche users' watch time, it would choose the former. That is what I think is true. I, of course, do not know about YT's algo, but I did work in RecSys's in the past.