The idea is to bring the UX of OSX Snow Leopard back, adjusted for today’s possibilities (better developer experience, AI, etc.). I’m developing a DE, SwiftUI/AppKit-equivalent, and a bunch of reference apps I‘m personally missing in terms of quality (e.g. Raycast/Spotlight, Mail).
You would want to adjust it for today's display and input technologies. A high resolution OLED display deserves a different UI design than a 6-bit low-contrast TN LCD display did.
Those principles survived CRTs, TN panels, Retina, touch, trackpads. They’re not tied to a specific technology.
Can you give me an example of a change in todays UI that was motivated by change in display quality?
There are a lot of places where I now see a miniature thumbnail preview of a file's contents, where in the 1990s you would only have seen an icon corresponding to the file type. Those previews are enabled partly by faster IO and processors making the preview rendering cheap, but also by higher resolution displays making the previews a lot more useful than they could have been at 32 pixels or smaller.
While it's not exactly a quality change as the driving force, the proliferation of dark mode UIs is a result of OLED displays that draw meaningfully less power with darker content, so pushing users toward darker UIs helps battery life. And it looks much better on a display with decent black levels than it would on a crappy LCD that washes out all the dark colors.
That's not really it. You could cache the thumbnails so it was never expensive to do.
If anything standards for performance were lower then (no 120hz displays) so people felt free to do more expensive things at the time.
The extremely heavy "pinstripe" Aqua UI existed because displays were so low contrast at the time that it didn't look nearly as heavy. A much higher contrast display that actually displays blacks properly means it'd look more like visual noise.
Going to launch a few apps powered by AppLib in the next few weeks and then continue with the DE.