> But I felt the ending was rather unsatisfying, because it simply stops after he succeeds—lacking the kind of depth we usually expect from a great novel.

I find this a lot with American TV and movies (not so much with books as I tend to read non-fiction).

Tying up all ends, sequentially and perfectly. It makes it all very unsatisfying.

> American TV and movies

I just thought of a perfect example: The Graduate. Many people like that uncertain ending—although they eloped, the camera keeps rolling, and we see them shift from initial happiness to confusion. A beautiful, simple ending is certainly nice, but an ending like this is far more unforgettable.

German filmmaker Christian Petzold often gets some flak for his ambiguous endings, but it's amusing that he actually follows European cinema tradition. It's his audience (even in Europe) that got more used to neat, fully wrapped endings from American media.