The creators of Wayland decided that it is not their task to handle remoting. You could argue that this demphasizes the issue, leaving it to insufficient VNC, dead projects like NX, or not yet production ready projects like X2Go (once they support Wayland that is).
That seems to be their decision but I can't imagine what's motivating them. How is the non-remote use case even relevant at this point? Is Wayland intended for console gaming?
What Wayland is not is a protocol designed for remote transport over TCP. Neither was X11, mind you. There are other, better, protocols like this, like RDP, VNC, and SPICE. These protocols use techniques from video compression and instead of shared memory.
You can use VNC and RDP with Wayland.
Also, VNC is nothing like the network transparency of X11. In X, I am able to run a single application on one machine, connecting to an X server running on a different machine. The application will be a first-class citizen in the user environment. This is in contrast to the VNC case where it lives in a separate desktop that is forwarded as a whole to be displayed in a window on the receiver side.
Apple made one massive simplification -- apps only run at 1x size, or 2x size, and nothing else. This isn't theoretically "nice", but (for me) covers most use cases, and seems to have made the implementation much easier, as you can still design your interface pixel-wise, and just let the OS double scale everything.
Gnome applications of recent vintage behave correctly, pretty much across the board. Firefox has some of its own configuration (for content, but the Gnome settings get applied to the UI), but behaves OK once configured. It's all the non-Gnome stuff that gets weird. Mostly games and music and graphics apps that don't use the system toolkit. Unfortunately, those are just the apps I most want to be able to cram a gazillion pixels onto the screen.
I'm tinkering with audio again, on both Linux and Windows, and VSTs, in particular, are awful. Unusably small, in many cases (VSTs are, IMHO, already the ugliest UIs in the world). At least most of my actual software works OK; FL Studio go an update recently that make it's UI vector-based, I guess, as it is fully scalable across any size screen, and looks really good at any size.
For reference on the ugliness of VST plugins (many of these are laughably expensive, like in the multiple hundreds of dollars for usually very simple DSP algorithms wrapped up in a ridiculous GUI):
https://www.google.com/search?tbm=isch&q=vst%20plugins
Now, just imagine them shrunk down to the size of a postage stamp...it's kinda like the thumbnails on image search, actually, on my 15" laptop display.
Wayland has a process for standardising extensions - write the XML file defining it and send an email to the mailing list, then respond to questions - if developers cared about Wayland, they could do it.