You answered your question of why Wayland exists right after asking it. X sucks. Wayland is a very significant improvement, I’m not sure why you think it’s a lateral move.

Also, X works for some cases, but not all, just lime Wayland. Using multiple refresh rates doesnt work well, HDR has no hope of ever working, and fractional scaling is horrible. Wayland has initial support for HDR and great support for the other two.