Apropos of various posts over the years: something that may not be obvious is that while it's true programs have gotten less efficient, it's also true that memory usage reporting has changed between OS versions*, almost entirely in the direction of "reporting more memory used".

It turns out that "how much memory does this program use?" is actually a really difficult question to define, with no single correct answer.

*I assume this is also true on non-Darwin OSs, but I know less about those