Paraphrased arguments against Blazor...
"JS gives us everything" -- I think the JS ecosystem is a morass of command line tools. That you need 15 different things to make a web app is just horrible. I don't dislike JS as a language, but I like even more the ability to write front-end code AND back-end code in C#. No need to recreate the same class as C# version and then JS version, etc.
"Microsoft is bad/proprietary" -- I've been a Mac zealot from the 80s but am embracing .NET Core and Blazor wholeheartedly. They're both open-source and cross-platform friendly. I write Blazor at work on a Windows machine and then come home and write Blazor apps on my Mac.
"No work for Blazor devs" -- learn Blazor and you've also learned .NET Core, (probably) Entity Framework Core, Razor, C#, etc. Lots of call for those skills. It's not like learning Silverlight in that respect.
I'm working on rewriting an existing app for our organization as a "test" for where we go from here, and while we still have maybe 30 days before we ship (it's server-side Blazor, not WASM), I imagine the next project we start will be using Blazor, too.
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