You just described X11's DRI (direct rendering infrastructure).

https://en.m.wikipedia.org/wiki/Direct_Rendering_Infrastruct...

X11 is utterly broken for multi-monitor setups with different resolutions at different scales (e. g. builtin laptop screen @1.25x, external display at 1x or some variation of that). With high resolution screens (e g. 4k at only 27"), that setup is not uncommon anymore.

(Wayland is broken in very many other ways, though, so you trade one evil for... 5 others).

Wayland's scaling for 1.25x and even 1.5x is not so great either, though it is slowly going in the right direction with wp-fractional-scale-v1

X was a very well designed system IMHO that could be evolved via extensions (e.g. how compositing was added etc.). It is sad that few people work on it anymore to fix such issues.

X isn't opinionated enough, and Wayland is even worse. While X has labels like "substructure redirect override" that in practice means "bypass the window manager" and tries to theoretically support multiple window managers, Wayland barely even knows what a window is!

Correction: Xorg doesn't have good support for this. I don't think there's an extension for it in the protocol either, but one could be created - just as it has for Wayland. Apps that don't support the extension should be scaled by the compositor as usual.

X11 has a reasonably solid core, though, while Wayland does not.

This actually doesn’t work with modern expectations.

Modern games are expected to work in multi-monitor setups and render in “borderless windowed” mode, so you can alt-tab out to multitask, or have a comms overlay. Single monitor single process gaming still happens, but a good 85% of setups (according to the Steam Hardware Survey) are not that. There are five games I know or that actually handle multimonitor natively of the hundreds I’ve played. So we need some form of cooperative multitasking for graphics with the window manager.

Modern good games are not expected to "render in “borderless windowed” mode, so you can alt-tab out to multitask"

Really bad games with slow multiplayer match making lobby and tiresome repetitive gameplay and bad UX where you need to look most of the actual game information on a fan wiki, or triple A games where you have to login and enter credit card information on a "launcher"... those are the ones you expect to "render in “borderless windowed” mode, so you can alt-tab out to multitask". Good riddance.