This resonate with my experience as well.

I had quite a few discussions recently with people who believe that if they target .NET Framework, it means they got stuck on C# 7.3 and nothing can be done there. And typically they got surprised that like 90% of all the recent C# features can be used with PolySharp or by manually adding some attributes manually.

Some people are scared that this is not officially supported thing, but Visual Studio actually heavily relies on that. VS itself is a full framework app, and Roslyn project (a.k.a. the C# compiler and the language service) uses latest language features targeting .netstandard2.0 (and ended up running as a full framework VS app).

So if something is good for VS, its good for most of us IMO. And Toub and Hanselman even mentioned that in the previous Build talk.