I wasn't old enough to remember it, but when search engines tried to do this in the 90s, it became clear that people preferred machine recommendations. See yahoo directory, look smart.
People preferred it because Google - at the time - had found a scalable solution which gave (mostly) the best results. Why should I search for hours through directories if someone give me what I want after only entering a few words? No one has found the "page rank of movies/series" yet, so I think HBO has a better chance here.
I'm not so sure -- I think the problem is no one has deployed it.
As a consumer, what I want is: based on my viewing history and/or shows I've said I like, show me more shows/movies I'll like.
What I currently get is: shows/movies that are in a similar style and genre to what I've watched or liked. The algorithm doesn't seem to take into account "good" vs "bad" movies.
The result is if I just randomly pick some movie from Netflix's "Because you watched.." recommendation, there's a very high chance I'm going to end up watching something I don't like because it isn't good.
As a concrete example, I just went to Netflix movies. "Because you watched Avengers: Infinity War...". There are 6 movies on the first page, 2 of which I've seen and have high Rotten Tomato scores (they are both Indiana Jones movies, with 88% and 85%). The other 4 have RT scores of 31%, 27%, 12%, and 3%. (Don't get me wrong, there are movies I do like that have low RT scores, and there are movies with high RT scores that I don't like, but generally a bad movie is a bad movie and more often than not there's a correlation with RT scores.)
Even if I could filter by "RT score > 60%" that would cut down on a lot of garbage, even if it means I might miss a couple movies/shows I'd actually like. This would change my personal perception from "The vast majority of content on Netflix isn't really worth watching" to something more positive. Note I still subscribe despite this -- there's still ample worthwhile content. I just don't watch things based on Netflix's recommendations alone.
Certainly it is possible to come up with something better than that blunt filter. So the question is: why don't they?