> some games have the most complex and information dense user interfacesCompletely different audiences and incentives. Gamers game because they want to; most people use apps because they have to, to get shit done and pay the rent. Gamers are motivated to inspect capabilities in order to get an advantage, to solve the gameplay puzzle, even just to kill time; people are motivated to get the hell out of apps as quickly as possible and go shopping.
I don't care about the capabilities of MS Word, I just want to type some stuff out. I don't care that Outlook can read RSS feeds, I just want to send an email. I skip every single onboarding wizard I can skip, because I honestly don't give a shit about 90% of "features" out there. If people cared about advanced features, we'd all be using Emacs.
> many UI problems would be solved by Apps replacing meaningless icons with actual text labels
I don't disagree in principle, but the reality is that text takes a lot of screen real estate, scales badly, and most people think text-heavy UIs just look ugly. We could definitely have better and more meaningful icons though; the "material" anti-skeuomorphing bullshit has inflicted a lot of damage on the credibility of UX practitioners, over the last decade. The 90s in comparison were a dream.