Once upon a time this was true. User-facing documentation was scarce (usually requiring internet searches). However, between unofficial package managers like homebrew, the excellent efforts of a few devs (LaunchBar/Quicksilver, PathFinder, Little Snitch, etc...), `osascript`, and the internet providing defaults documentation for obscure apple apps, I always felt like I could get the system to behave the way I needed it to.

This started changing about a decade ago. The first time I noticed it was when Apple bundled all of the services involved in NAT into a huge binary (this would have been about OS X 10.8 or .9). You could turn it on or off, but there was no longer a built-in way to serve DHCP on both ports.

There's been a steady progress away from tools aimed at the entire skill gradient and towards the lower end of that gradient: Around 10.9 OSX got new file open/save dialogs, which were infinitely better if you used a mouse... but lacked any cmd-key shortcuts.

Gatekeeper has made it progressively harder for system tweaks like LaunchBar or Little Snitch to exist, and I've had to wrestle with SIP more than once.

In summary, earlier versions of OSX are perfectly fine (my one remaining mac is on 10.10), but Apple has not been doing itself any favors with the dev community in more recent iterations of the OS.