In particular Blazor offers two interesting approaches (“hosting models”):
1) a websocket-based HTML sync layer, basically shipping over the smallest amounts of render state from the back-end. This is as close as you get to having, essentially, a server-side rendered page that is then updated in real time.
2) a wasm based approach where the whole application is delivered to the browser and you make the API calls.
Both have you writing majority of the code in C# and Razor templating syntax. Yes, you make an argument that well it’s technically still JS running it. But this becomes an implementation detail that will be ironed out, because technically the browser is written in C++, but we look beyond all that. And so on and so forth.
Now, I’m not saying I expect the world to move to .NET. Far from it. I have been preaching for a language agnostic browser execution engine so that I can write not only my logic, but my layout and styling in whatever language I want to, whether it’s Ruby or F# or Lisp, and have the browser execute it via its own internal “assembly code”. Except I’ve been parroting this idea since mid-2000s and we have at last finally started down that road.
I think this is where we are headed, and I don’t think it’s far fetched.