Have you even used macOS on a HiDPI display? I use this every day on several setups and it shines at handling this. Windows, while it can do HiDPI as well, it's basically become a turd in terms of user friendliness and experience.
Option key while choosing the "size" desired in Screen settings. Gives you more options and there's a solution for everyone. I think my resolution is 2640x something on my 4k. Crisp and large enough, although some would find it too small.
I’m not saying it’s a lack of resolutions to choose from.
Let’s say a default button is 100px wide with 10pt font size and I have a 1920x1080 screen.
If I choose “125%” on Windows, it will render the button
125px side with 12.5pt font. With the caveat that I can render fewer buttons on my screen.
On macOS I just need to pick a lower resolution, and then after al UI elements are rendered, scale it up to 1920x1080. This results in a scaled up and thus not pixel perfect and thus blurry picture.
So Windows renders bigger UI elements at native resolution. macOS always renders a button 100px wide, you can just pick a lower resolution on a high res screen so those 100px seem bigger.
You have a good point with non-HiDPI screens like a 1080p screen, but I guess that's falling out of fashion anyway. With 4k screens the problem does not exist. The Windows solution is certainly an engineer's approach, but overall it's not necessarily the best when it comes to accessibility. Look at macOS accessibility settings - it's comprehensive.
