Tons of stuff aren't in wayland that are actually graphics and window related. Wayland just forgot about it, then later on people realized that their design was far too primitive and simplistic.
DMA buffers, color management and pixel formats, scaling and DPI, image and video capture, tons of keyboard and mouse related things, all initially forgotten, now incompatible extras that are inconsistently implemented, frequently broken and forever in beta/staging/unsupported hell...