In 2024, with GNOME 45, Wayland, and 1.25 fractional scaling, regular DPI displays still look better than HiDPI displays. This is a photo of Discord on two laptops side by side.
The blurry one is the HiDPI display from Framework 13. The sharp one is a regular DPI display from Dell XPS 13. Both laptops.
The difference is even more stark in person.
Even the screenshots from the Framework are blurrier than the screen shots from the Dell.
Apple, too. The 2012 MacBook Pro had a high DPI display, and everything scales normally even when dragging windows over to non-HiDPI external monitors.
That’s not even getting into the mobile OSes, which have to deal with nonstandard display sizes and resolutions all the time, across multiple settings for accessibility.