Hasn't Microsoft largely hitched their horse to Go these days, though (not just this project)? They even maintain their own Go compiler: https://github.com/microsoft/go
It is a huge company. They can do more than one thing. C#/.NET certainly isn't dead, but I'm not sure they really care if you do use it like they once did. It's there if you find it useful. If not, that's cool too.
I'm sure Microsoft could find the money to do a lot of different things. But why that instead of the infinite alternatives that the money could be spent on instead?
It is a huge company. They can do more than one thing. C#/.NET certainly isn't dead, but I'm not sure they really care if you do use it like they once did. It's there if you find it useful. If not, that's cool too.