1) We live in a multitasking world where people are half watching netflix and half on their phone. TV plots typically develop in smaller chunks, requiring less attention.
2) Most people do not set out to binge watch multiple hours of netflix, but instead get caught up in the shows. Movies feel like a larger commitment, even though many times people watch for the same total length of time.
3) Binge watching often happens because the TV show model is to often end on a cliff hanger.
All the Star Trek series and films are on Netflix. Wouldn't it be great to have a playlist of every episode by original air date? (So you don't get confused when Deep Space 9 refers to an event in First Contact?) Wouldn't it be awesome to have a playlist of only the top 20 Voyager episodes, so you don't have to suffer through the awful ones?
It surprises me they haven't implemented this. If they did, any user could solve your problem of putting a movie series in order.
Of course I also wish they had a "back 30 seconds" button for when you miss a line of dialog, and that's never been done either. Sigh. It seems like all their revenue is going into making Marvel shows and zero into software development.
It has far less to do with "not noticing" and much more to do with the algorithms knowing what you might want to watch that you didn't already know you wanted to watch.
I suspect it's as much the latter as the former.