[ongy]

You are saying that as if the part of the X11 protocol that's reasonable to run over the network was the better API that application developers are simply too lazy to use.

While the reality is, that toolkits (and applications) used to use those APIs and were revamped to use the DRI APIs and general bitmap based windowing. The old APIs don't support double buffering, access to GPUs with modern APIs (both opengl[indirect sucks] and Vulkan). They don't provide modern font rendering, or any kind of graphical effect (distortions) that UI people might want to play with.

They would be significantly worse for anything displaying animations and one of the most common client libs (libx11) is serial and thus horribly latency sensitive.

The advantage of VNC isn't lossy compression. Which isn't forced by it either. But it handles networking better with bitmaps. And has improvements like acting as a screen/tmux style connectable session for graphical applications. Both VNC/RDB can also support showing the server's desktop if it has one, not just running other applications than currently open elsewhere.

The only advantage of old style X11 was that it's ubiquitous. But since it hasn't been used in ages since it doesn't work well with modern computers/UI frameworks that advantage is gone. And there's 0 reason to try and reimplement that in a new windowing protocol, when there's objectively better choices out there already. Local optimized windowing is a different beast than network capable.

[customkitchen]

You might also want to note that the fantasy of being able to use the same protocol to drive the local display and also operate over a network, is long dead. It seems like a clever idea but it doesn't actually work. It ceased to be a thing entirely the moment wide area networks became popular. The local and remote cases are two completely different situations that need their own individual attention. Even when developing against X11 protocol you still have to consider this in modern times because the DRI extension is not available over the network.

Compare to a protocol like RDP which is extremely optimized for efficient and secure network operation, but is also way more complicated as a result, and it would be foolish to use it on a local display server.