Also, you were far more likely to get actual documentation back in the day. You're never going to get a detailed first-party technical reference for today's Apple computers (at least not without being Big Enough and signing a mountain of NDAs); compare that to the Apple II having a full listing of the Monitor ROM, or the original IBM PC Technical Reference Manual.

The very existence of those manuals improved the software, as the technical writers were trained in a different discipline than programming, and it really showed.

Even some well-documented modern software is obviously documented by the programmers and programmer-adjacent.