I agree with you, but I dont think lack of development on one front can be justified by some work happening on the other front.
I think all the scalability model of linux desktop is broken, you cant have a stable, clean and secure desktop environment by hiding to user the processes under the hood and adding layers over layers of complexity and GUIs.
I hack frequently with wayland and X and I think they either can be just so simple and so good, all the problems I find are in the unnecessary garbage on upper layers.