I think it mostly explained by that in earlier days most people who dived into programming did it because it interested them. Then it became one of most lucrative career path, and naturally it saw surge of people, who do not share same interests. Relative amount of people invested in dive bombing into meaty details dropped, but it quite possible that absolute amount have not declined by much.
While GM decides what monsters to throw into players, they still need to know what they could use without it being either underwhelming or overwhelming. You dismiss this simply by saying: “just be a good DM”.
Disadvantage of having to look up rules then you don’t remember them could be mitigated by just saying: Look guys, I don’t remember ruling now, so not to break the flow, I will rule it this way, and look it up later.
So while for most players rule heavy systems are less accessible, they are actually more accessible for many DMs, and since mastering have much higher barrier of entry, such systems at least should not be dismissed outright.
Turing Complete
It is a game about building functional computer by combining logic gates. Game arranged in series of small puzzles to make it digestible for people without electric engineering degree like me. You slowly build new components, so you can use them later as higher level abstraction until you get to the point of having to program your own computer to solve further puzzles. If you curious how computers work, this game is a gem.