Why? C# fits the bill for everything I want to do. It's fast enough, it has great IDEs, it runs almost everywhere and there are more UI frameworks than there are JS frameworks /jk ;).
I have almost 15 years experience in it, why would I slow down my next projects by using a language I'm not familiar with (as long as C# fits the bill ofc). Learning a new language isn't a hobby for me, it has to be useful to me (I learned Flutter because MS Ui frameworks aren't a panacea).
So then we come these kind of assertions like Go compiles faster than any other AOT language, it doesn't have a runtime, its performance beats Java/.NET and so on.
Note the difference between “Go is better for certain cloud applications than Python, NodeJS, etc” and “Go is better than all other languages, full stop”.
https://www.techempower.com/benchmarks/
You should learn to write some Go code then.