this "device-agnosticism" is also the source of many of X11's modern problems. Because the X server has to handle all rendering and input, it acts as a middleman. For every frame, an application has to send rendering commands to the X server, which then composites the scene and sends it to the display. This extra step introduces latency and makes it difficult to implement modern features like smooth animations, variable refresh rates, and HDR.
In contrast, Wayland's design is based on the idea of direct rendering. The application renders a frame directly to a buffer in memory, and then the Wayland compositor takes this finished buffer and displays it. This approach is highly efficient for modern GPUs and display technology. The trade-off is that it ties the display protocol more closely to the graphics hardware, but this is a necessary step to achieve the high performance and low latency that modern users expect.
"Wayland makes some assumptions which will be wrong in 10 years."
This is a fair and common criticism. Yes, Wayland assumes a graphics stack that is based on OpenGL/Vulkan and a kernel with a Direct Rendering Manager (DRM). This works well today because modern Linux graphics drivers are built around this model.
However, an X11 advocate might argue that this tight coupling could be a problem if a new, fundamentally different type of display technology or graphics hardware emerges. With its modular design, X11 could theoretically adapt by adding new extensions.
Wayland developers have addressed this by keeping the core protocol simple and extensible. New features, like HDR or adaptive sync, are implemented as extensions to the base protocol. The hope is that this design allows Wayland to evolve without the bloat and complexity that burdened X11. While it's impossible to predict the future, Wayland's developers believe that its modular design is flexible enough to handle future changes in display technology.
Which I think is fair.