I find it hard to understand what I’m supposed to address from your monologue, but I’ll go with one thing that stuck out to me.
What does this have to do with app developers? GNOME, Plasma, Wlroots, and Smithay use the Wayland protocol. If app frameworks use the Wayland protocol, then they’re compatible with GNOME, Plasma, Wlroots, and Smithay. Apps won’t work if GNOME, Plasma, Wlroots, and Smithay were compositors with their own, separate, incompatible protocol. Or the Wayland protocol in that hypothetical world is so poor that Wayland compositors deviate so much from each other that app frameworks must support each compositor individually.