The key difference between TV and the vast, vast majority of movies is there is a certain contract that exists between the audience and the latter that isn't present with the former.
If I sit down to watch a film (or at least one that isn't explicitly part of a block buster movie franchise) there's an implied contract that I'm going to see a story that has a beginning, a middle and an end. That ending may be an 'open-ended' or ambiguous ending, but will definitely be an ending.
That contract simply doesn't exist on tv any more. If I sit down to watch S1 E01 of just about any tv show, I have, with very few exceptions, absolutely no way of knowing if I will ever get an ending. Obviously, at some point it'll stop, but that's not the same as an ending.
And I can't stand that. I'm sick of watching a dozen hours of tv only to find that the series finished with a kind-of-an-ending but mostly a to-be-continued-please-don't-cancel-us-pretty-please. How many hours do I have to watch to get an ending? Am I even even going to get one before the show is cancelled. Or worse, will it just go on for so long that by the time the end comes it'll have fully jumped the shark?
This didn't use to be the case. *Grandpa Simpson voice* Back when I was young tv drama could be put into two broad types: mini-series and syndicated shows. Mini-series were basically long, cheap films broken into tv sized chunks. And syndicated shows had a story, complete with a beginning, middle and end, in every show. That way that could show regular repeats on any given channel and not worry if the viewer hadn't seen every prior episode in order.
I wasn't watching Quantum Leap to find out if Sam got home. I was watching to find out what amazing story would happen this week. It was nice to have that final episode but I'd still love the show if it didn't.
Most people seem to think that modern tv is in some kind of 'golden age' but for me it just takes too much time. If I watch a series that gets stops without a proper ending I just feel like I've been cheated. That time feels wasted.
Stories have endings. Otherwise it's just a soap opera that got cancelled.