The first big problem, which you see on Netflix as well, is that a recommendation engine really falls off in efficiency when your selection is thin, and the original dream of streaming every film is never going to happen because of a price squeeze from the content side (hence Netflix moving into production and focusing on exclusive content).
The second, perhaps bigger problem (particularly for our audience) is that there is only so much metadata that you can pump into a film database that will tell you categorically if someone wants to watch it. People like to be delighted by discovering a new film, not because it is somehow akin to 20 other films they liked, but because of where they are in their life now, and the contemporary meaning of that film. I know curation has become possibly the most annoying buzzword in SV circles lately, but it has been our approach since 2007, real actual curation by human beings—not algorithms that purport to be "curatorial" on a pitch deck.