To be fair, the norm for anime and most series in general in Japan is to tell a story with an ending.
There are absolutely exceptions to this - shonen stuff like Naruto/Dragon Ball/etc tends more toward the standard US model of keep writing as long as it’s selling. (Outside of anime there are long running soaps and so forth - but most live action shows are written as one season and done.)
I think that whether people are consciously aware of it or not, it’s definitely part of the appeal to have a show that tells a story and ends, instead of drawing things out as long as possible because it’s popular then limping to a rushed conclusion once cancellation looms.