If I had to pin most of this on anything I’d pick two:

- Dribbble-driven development, where the goal is to make apps look good in screenshots with little bearing to their practical usability

- The massive influx of designers from other disciplines (print, etc) into UI design, who are great at making things look nice but don’t carry many of the skills necessary to design effective UIs

Being a good UI designer is seeking out existing usability research, conducting new research to fill in the gaps, and understanding the limits of the target platform on top of having a good footing in the fundamentals. The role is part artist, part scientist, and part engineer. It’s knowing when to put ego aside and admit that the beautiful design you just came with isn’t usable enough to ship. It’s not just a sense for aesthetics and the ability to wield Photoshop or Figma or whatever well.

This is not what hiring selects for, though, and that’s reflected in the precipitous fall in quality of software design in the past ~15 years.