Totally agree. The .NET team itself is probably costing above 100 million every year, probably more. Microsoft is not ditching .NET, they are heavily investing it.
The office division is implementing some code in Rust while the same division just posted a success story of their usage of migrating some low latency server code to .NET Core.
Microsoft is a big company and like any other they use JS, TS, Rust, C++, Python, Go and so on. The only thing they do not use is Java ... And I am not 100% confident there.
So let us congratulate Rust for entering the office domain and stop writing swan songs about .NET.