Yet sometimes the only reasonable guess is that they coded in undocumented brainfuck.

I do that every time my wife has a problem on the phone or tablet. “Try this button then wait then this button.” It works all the time.

Quality control is expensive, and all they ever do is complain about how my brilliant idea to save money will kill more trees or some shit.

If I remember right, the devs of Nickelodeon All Stars Brawl and the devs of the GTA Remasters experienced something similar. They had bug fixes ready to go but had to fight with the rightsholders (Viacom and Rockstar, respectively) to be allowed to publish the patches.

Honestly it’s way worse when you see simplistic games with problems that you know personally wouldn’t take a long time to fix.

See the GTA loading bug fiasco.

Nobody in the whole company or QA thought “why does this take so long to load? Maybe I should check that?”

Yeah, it just makes you annoyed, especially when having worked on (some product) and it is years later and you are like, “we fixed this 10 years ago, you morons, how did you let this regress?”