Many (most?) don't or can't be bothered so the end result in practice is that it doesn't work. Microsoft has been chasing the HiDPI fairy for decades and the situation hasn't really gotten better. They still ship software (both in and outside the OS) that isn't HiDPI aware.

Retina prioritizes making it easy for developers to adopt: Double the size of artwork, points are 2 pixels, Done. Are there quibbles? Sure. But millions of people are looking at HiDPI screens where every single thing in the OS and all third party apps they use fully support 2x.

No one lives in the magical world where arbitrary scaling factors are supported. Doing that as a developer is just too damn complicated when @1x + @2x (and maybe @3x) makes 98% of people happy and is vastly less work.

If even Microsoft can’t be bothered, what do you expect from app developers?!

Apple has never settled for “fine” either it’s great or it gets cuts at some point.

>if you know what you’re doing as an application developer. Apple also tends to avoid wading into footgun waters to keep quality (for 3rd party devs) as high as possible across the board.