If you want to make it easier to develop alternatives to GNOME, it would be best to start putting more reusable features into libraries, and getting all desktops (including GNOME) to use them. That way you have a common baseline that everyone can depend on. That may seem counter-intuitive but it is the only way, libraries provide implementations and it is actually the implementations themselves that are the important part to users, not anything that upstream is doing. The simplest example is something like Mesa. All the Wayland servers want to support hardware acceleration, so they all implement the relevant extensions, and then they're able to support applications that talk using the Mesa libraries.
> So they focus only on the small subset of things that every desktop agrees on
It's the old "but I can't do screenshots or screen sharing" again. The desktop may agree on this, but 90% of the users are like "I don't care, just make it work" - and by catering to what desktops agree on and completely ignoring things that at least some good percentage of every desktop will use, they kinda made a mess. It might be an architecturally superior mess but not even the people who have been tinkering with their Linux boxes for 20 years seem enthusiastic about wayland. Not everyone wants to first implement features in their window manager of choice.
I don't know what this refers to. The screenshots and screensharing are done through the xdg portal and pipewire. That's as "standard" as something across desktops can be, but like I said it just is done in a separate library/daemon rather than being in wayland upstream. You don't need to really implement anything in your window manager of choice if you already have support for those, you just use pipewire. They all agree on it. The implementations haven't ignored this, you're telling me I didn't get to the right conclusion but your conclusion is to just keep barking up the wrong tree and hope they change their mind, when they have even less incentive to do that now because the feature is already implemented elsewhere in a much better way.
>but not even the people who have been tinkering with their Linux boxes for 20 years seem enthusiastic about wayland
I don't consider this to be a problem. The tinkerers get most excited when you hand them something with a giant config file (e.g. xorg.conf) with every option under the sun that they can tweak and watch it fall apart. Most upstream maintainers I've talked to would very much like to get rid of these giant config files because they are completely untestable and unmaintainable. The tinkerers cannot have their cake and eat it too.
My understanding is most of the work is, deliberately, not in Wayland itself. In fact if you read feature and bug discussion between users and Wayland devs, it kinda seems like Wayland doesn't do much at all and has no interest in doing more.
I haven't looked into it, but wouldn't be a bit surprised if RH had a hand in that architectural decision. Definitely makes it harder to compete with Gnome.