Yes, there are two Blazor variants. Serverside Blazor is basically the same thing as Phoenix Live View, client side Blazor is providing some optimized Mono runtime as webassembly.
I have no idea. Probably longer. But it is the same idea. The big gains come from going back to the simpler server side programming model. I'm working on a big Angular application right now for which something like Live View would be the ideal fit. That said, a switch to Elixir would be a very hard sell in my company. Blazor would be easier because it's .NET.
I also don't know enough about c#, to comment on this being a risk for blazor but having the BEAM's process isolation is absolutely critical to minimizing programmer error from turning into a let's say a DOS attack risk, or possibly worse.
I worry that all these other platforms rushing to emulate liveview are missing that extremely critical component of this model. If you aren't certain about what I mean, I suggest watching Sasa juric's "the soul of erlang and Elixir" video where forward progress of the system is unimpeded by a panic or a process that attempts to hog processing via an infinite loop, both are detectable in the running system, and able to be easily identified (down to the malfunctioning function name) in the in-prod system.
