Of course people can learn how to navigate more complex interfaces than Twitter, but why? For what? Certainly not for the purpose of social entertainment like Twitter et. al. What a waste of time that would be!

> Like, imagine how much better many interfaces could be if we taught basic regular expressions in schools?

Ok I've imagined it and I think the answer is "not much better". Pretty much all of us here know regular expressions and we all use interfaces purpose-built for people like us who know regular expressions, but beyond searching and replacing, this isn't a particularly powerful interface element. Like, it's fine and all, it's just not revolutionary. Searching could be made a bit better with widespread understanding and use of regular expressions, but little else would change.

I really think you're underestimating the extent to which interfaces are already really useful to the people using them. We have endless scrolls in social media, which is what people want for the mindless entertainment they're seeking. We have Photoshop for photographers, Ableton for people making music, really good CAD software, tons of good film creation and editing software, the Bloomberg terminal for financiers, really good editors and IDEs for people making software, etc. etc.

Of course there are exceptions, places where there is real room for improvement (I think streaming video interfaces are pretty bad, for instance), but for the most part interfaces are what they are because they serve their purpose well, and not because people are lacking education in their use.