> Can .NET deploy a static binary nowadays?

You can, as sbelskie mentioned below. In .Net 6, it's available as a Preview [1]. But it's going to ship with the main framework in 7.0 [2].

The preview works quite well. You can build self-contained, smaller executables, and shared libraries callable from say, C code.

[1]: https://github.com/dotnet/runtimelab/blob/feature/NativeAOT/...

[2]: https://github.com/dotnet/runtime/issues/61231

LINQ is best when used on in-memory object graphs, partly for the reasons you brought up, and partly because then you're not dealing with weird limitations or deviations from how functions normally work etc. For in-memory queries, it's basically just a very advanced form of sequence comprehensions.

(I also suspect that the vast majority of LINQ code in the wild is of that variety, rather than Entity Framework etc.)

True of nearly all ORMs really. LINQ on objects basically makes C# a very nice functional language. Dapper is arguably better for database but then use LINQ in those results is very nice.

> Can .NET deploy a static binary nowadays?

You can bundle everything in a single file but that file contains the runtime, so even small Hello World apps are 50MB+ last I checked, though there have been some improvements recently with trimming and AOT is hopefully coming next year with .NET 7.