This exactly is the point. Wouldn’t it be nice to just use apps without extra steps? It would make Linux better for non-experts.
You can’t even isolate X applications without running other X.org because there is no permission control once the application has access into socket, and with socket it can see everything. And you can’t really rework that. Sometimes you need to rewrite whole thing.
Applications cannot normally spy on you unless you run everything in root. It is X.org which provides access for keystrokes and windows.
> Xorg is an open source program, you can't "end of line" an open source program, it isn't Visual Basic 6 that died because Microsoft decided it should die. As long as someone wants to improve it, it will get improvements.
Because the design is bad, it gets harder and harder to add new features. Fixing bug introduces two new ones. Complexity makes it hard to approach project and control everything. Red Hat has maintained it so many years with proper funding, otherwise who knows what would have happened.