Although that picture gets clearer as I realize their baby (web in .NET) was called ugly for the last decade so they are salivating for Blazor to feel at home again on the web. (zing!) OK back on track and in all seriousness, Blazor is a rich platform to build modern apps using C#, and I do fully appreciate the excitement of being able to run the same code on the client and server. This is a significant strength in addition to several other bullet points about the stack.
History will show though without JS, the development community as a whole I don't think would be near where they are today and still creating per-platform apps like 15 years ago. The ability to write-once and deploy platform agnostic for the last 10 years is unparalleled until recent advancements. It's historic significance can't be ignored.
Also there is no hidden agenda here to resist change or remain some kind of isolated JS developer wearing blinders. I'm not that dogmatic in my career path as I've typically moved along with change remaining modern to where mainstream development has gone, and not tried to hang on to a stack out of stubbornness. I'll adopt change as the community does, and always excited about the advancements of the future.
Being pragmatic and assessing the current landscape, I think the real step forward for folks not purely on a single stack like C#/.NET, or any narrow/single stack for that matter will be a hybrid one (by definition hybrid); at least in the beginning. This is even suggested straight from the horse's mouth: https://webassembly.org/docs/faq/
Here are some interesting examples that do just this:
It's important to continually modernize our stack and remain fluid with the direction the community guides us. WebAssembly plays an important role in the future of all types of development. What are your thoughts on how this will evolve?