Why do so many anime series just stop?

Anime often runs ahead of its corresponding manga, leading to filler episodes that no one likes, leading to cancellation. This is what happened to Rurouni Kenshin, for example. As I understand it, however, Full Metal Panic! was released in three separate series. Have you seen them all, or are you just at the end of one?

Anime are almost always based on a manga, and at the time the series is commissioned, the manga is still running, therefore there is no real ending in the actual source material.
That is why the anime has to make up its own unfulfilling ending or or it ends on a cliffhanger, but then are not renewed for another season (usually a season has 12 or 24 episodes), due to a lack of popularity (not necessarily due to fillers, but also because the anime didn’t turn out good enough itself).

Neon Genesis Evangelion has a conclusive (if not satisfying or even comprehensible) ending. I highly recommend it.

They don’t want to end up like Naruto and Bleach. Those series are seemingly endless, but the series would be better if they bowed out gracefully.

@SavoirFaire Done the whole series.

Anothet good example is Black Lagoon, they did 5 OVA’s and it basically died, I think the manga stopped :(

@XOIIO Ultimately, it may be that the anime writers would prefer to have the series reflect a moment in time for the characters—an important section of a larger story—than write a Gecko Ending that will wind up being hated by a lot of people. It’s a difficult artistic choice.

@SavoirFaire Yeah, but a lot of them just leave off when the story just picks up in one part like FMP. It’s wierd, but oh well.