I mean, at least with web browsers they usually converge on a common spec eventually, and most of the time you just have a bit stupid repetition in your CSS for a bit. Wayland compositors seem to be actively against this kind of process.
It's a very forced comparison trying to swap in the web's security model, where one runs untrusted code from arbitrary third parties automatically, for a personal desktop computer context where a single user is in complete control.
Uh... lived experience? Try getting keyboard and mouse sharing working across all the waylands with the same software. Not having most of the features in the standard implementation leads to fragmentation which apparently you haven't run into with your use cases yet.
I still don't know how people twist this obvious success into a failure.