You know, you're right, I never thought of that. However, the anime director should be able to choose how much material to cover in a season so the story reaches a natural stopping point. As the person in charge of the adaptation, they should be able to control the script and how much material is adapted. Too many anime feel like they went along from week to week with no plan as to how to wrap things up, and I know that can't be the case, so it shouldn't feel like it either.
To be fair, I've seen a
multitude of anime adaptations cripple their pacing and the story itself in order to get to a "good end point."
Worst case, story stuff and characterization and even whole plot points can be cut, rushed, or rearranged in poor ways.
Meanwhile, an anime that "just ends" tends to make for a superior product when you then binge seasons, and makes it the superior version for all future watchers.
Funnily, I think shounen manga are the easiest to adapt pacing-wise since, depending on magazine of origin, authors and editors are actually conscious of the "2:1" rule of thumb of anime adaptations, and are far more certain that a successful manga will get an anime eventually.
Moderb manga is generally also faster paced, so sn anime director gets more bang for their buck per chapter, which makes the rule of thumb flexible.
Action shounen can be even easier, as action chapters defy the 2:1 formula but can be as quick or as long as the director could want. That gives the director considerable power over the pacing of the season as a whole.
I find that really amusing since action shounen literlly was the origin of the
"horribly paced anime nexttimeondbz" stereotype, yet modern conventions has flipped the script.
LN anime adaptations often have bad pacing, but the
manga adaptations of LNs tend to have great pacing. I rarely bother with anime adaptation of an LN if I already read the manga adaptation.
Seriously, 9/10 the manga adaptation will be better than the anime by a wide margin, and often better than the LN, too.