Developer and corporate status games select for political skill and self-indulgent overcomplexity, with added spice from dark patterns. There’s no reward for UI/UX/internal simplicity and elegance.
The culture at some companies would have been hugely improved with a few literal angry-users-with-pitchforks moments.
Then why do it? I like a good UX just as much as you, and I value simplicity, but people just want "good enough". And that is all there is to it.
I think you've built a strawman. People who use computers to get shit done might pay lip service to things looking good, but at the end of the day they want a tool that does the job without a lot of bullshit. To the extent that the kind of person you're talking about exists, they are consumers who live in tablet land and should be ignored for desktop/workstation use cases.
I have to add that most computer I see of my friends are extremely snappy, I don't really see what you are talking about.
If the latency begins to cross a threshold and begins to be inconvenient or distracting, it is time to step and think that may be the pretty UI is too ahead of its time, and we should stop making the UI prettier than it can be at this time.