Blazor+MAUI has absolutely been a focus of development from the start. What Im seeing with this is that MAUI is somewhat throwing in the towel and hoping to offload to avalonia to take the torch of development. I'm sad, because I was pretty in the weeds with MAUI at the start, as I was building a greenfield app at the time. It had a ton of potential to be a reimagining of Xamarin and how it fit into the broader .net ecosystem but they just shot themselves in the foot (both MAUI team and the broader MS dev efforts).
I havent been in that space for a couple years now so maybe they have gotten better, but I doubt that. I appreciate the heroic efforts of the MAUI team, but I think its just the unfortunate reality.
WASM is just one of the platforms that Avalonia supports and so, if you run MAUI on Avalonia, you can run it on WASM.
If you do that though, it is going to be like rendering any other desktop GUI toolkit in WASM. It is not a web app. I mean, it is cool you can do it and MAUI in WASM is better than no web capability at all I guess. But you would never set out to create a web app in MAUI.
MAUI on Avalonia on WASM is really a modern replacement for Silverlight. And it will likely be about as popular.
The really cool thing is being able to target the Linux desktop finally. A lot of people will love that.
And, while MAUI was meant to use native controls on each platform, many people may prefer the Avalonia approach of having your app render the same everywhere.