.NET has had a hard time shaking off that old stigma, and to be fair, by the time it was really good, a lot of places already moved on to other tech (in particular, Go) .NET missed its window to escape the enterprise and despite being great, will probably never be seen as sexy.
I love it though. It's by far one of the most productive frameworks, and C# is pleasant to work with, and F# even more so.
Because it's not that great, really.
The performance isn't that great in real-world scenarios (remember when they had to lie, in that "one" incident)? Even today the tests look NOTHING like actual idiomiatic .NET code.
Secondly, .NET developers tend to target a particular set of DevEx that I don't personally understand but that's not the problem, the problem is the DevEx has end-user effects; they simply just don't give a shit.
Anything past a simple B2B crud app in .NET is basically an uphill battle in real companies. It never works out, it's always more complicated than it needs to be.
But hey, no one gets fired for choosing MS. So here we are.
If you drop the religious zealotry, there's simply not a lot left.
I have.