Films can have the same problem.

Notably the 4th film in the “Divergent” series was never made, although we got the first 3. The 3rd was a rushed failure.

https://en.m.wikipedia.org/wiki/Divergent_(film)
https://en.m.wikipedia.org/wiki/The_Divergent_Series:_Insurgent
https://en.m.wikipedia.org/wiki/The_Divergent_Series:_Allegiant

Similarly, the film adaptation of the “His Dark Materials” series sputtered out after one film, Golden Compass:

https://en.m.wikipedia.org/wiki/The_Golden_Compass_(film)

It would take TWELVE YEARS to reboot the franchise as series television for HBO.

Percy Jackson and the Olympians was another notable failure which somehow got 2 films out of a 7 book series:

https://en.m.wikipedia.org/wiki/Percy_Jackson_%26_the_Olympians:_The_Lightning_Thief

https://en.m.wikipedia.org/wiki/Percy_Jackson:_Sea_of_Monsters

It also would see a streaming reboot, this time 10 years later on Disney+

Even the perennial classic Narnia books had trouble in the film space, getting quite good adaptations of the first three books of seven before vanishing:

https://en.m.wikipedia.org/wiki/The_Chronicles_of_Narnia:_The_Lion,_the_Witch_and_the_Wardrobe

https://en.m.wikipedia.org/wiki/The_Chronicles_of_Narnia:_Prince_Caspian

https://en.m.wikipedia.org/wiki/The_Chronicles_of_Narnia:_The_Voyage_of_the_Dawn_Treader

Season 3 of a TV show comes with a significant wage increase for everyone involved, so 3 seasons (at least) is something that the sellers of a show always want, but the buyers are trying to avoid.

On Netflix, it’s become a pattern of all shows only getting 1 or 2 seasons, unless they’re mega-hits, or dirt-cheap to produce in the first place.

How well a show wraps up after 2 seasons often depends on how much the writers want to do the streamer’s job for them. Tokyo Vice was a (rare) example of a good, self-contained, 2-season show.

Different financial goals. Movie series are designed around a hype cycle to put out a major blockbuster every few years or whatever and produce massive ROI at the box office. Word of mouth and reviews matter; if it isn’t widely liked, it’ll get less revenue.

Series are produced by streaming providers primarily to entice new customers on to their platform and rake in subscription fees. Once they have the customers from season one, there’s less incentive to keep pumping money into the series. They rely on customer inertia and make it difficult to cancel a subscription to keep you around.

As an example of the opposite, there’s Warcraft. I personally loved the movie but not enough people did, so it never got a 2nd movie.

Money.

TV is like making cheap movies. As an investor you can calculate your return on investment every time an episode goes to air. If you’re on a winning streak, you’ll make more, if not, you’ll pull out and the show is cancelled. Many TV shows never get past the first pilot episode.

Making movies gives you potentially a bigger payout, but only if it’s a hit, so an investor will do everything to maximise the chance of success. Massive budgets, known stars, etc.

In the end it’s all legalised gambling. If you’re lucky, something interesting comes from it, more often than not it’s Waterworld … yes, there are worse movies, but you won’t recognise them … and yes, it made a profit … eventually.

Worst performing movies of all time: https://en.m.wikipedia.org/wiki/List_of_biggest_box-office_bombs

Series start with a concept for 2-3 seasons at most, nowadays often just one. If it’s successful, writers need to come up with an extension fast, since nobody wants to wait for the next one for 5 years. Sometimes they are greenlit halfway through the screening of S1 and they want to start filming half a year later, so there’s not enough time for due process with proofreaders, test audiences etc. as you do with movies, where sequels often come several years later.

The success of a TV show can be gathered in real time. A movie needs to be complete before anyone knows about it.

So, they are going to make sure that movie is as sellable as it possibly can, because they only have one chance. The TV show can get tweaked as it goes, and sometimes milking a cash cow doesn’t result in quality. I think of Family Matters back in the 90s. It was a decent family sitcom, but EVERYBODY loved Urkel. So much so, that the last few seasons were essentially the Steve Urkel show. That’s who everybody wanted to see, but the show was complete trash. None of the storylines made sense anymore, and they had Urkel playing Urkel clones because MORE URKEL, MORE MONEY!

Or, of course, it loses popularity and then it gets canned.

Consider, if you will, the rambling, incoherant Star Wars franchise. That series has been too long for its own good for years. So its possible for movie series to ramble. James Bond, Alien, Avatar. Where movies are based on a book/comic they tend to be richer stories due to the increased volume of detail in the source material.

Personally I prefer a movie though, because of the consistent ability to tell a story with a guaranteed begining/middle/end.

Because STOP WATCHING TV!!!

You’re clearly cursing all the good shows, and all we’re left with is crap like “the bachlor”, and “who wants to shoot a billionaire?”

Yeah, a movie is 2-ish hours. A season of a show runs for at least 22 episodes or 200-ish hours.

Lots of good answers here, the topic is often discussed on !showsandmovies@lemm.ee