And LINQ is not the enabler for functional programming, rather I'd say it is itself enabled by other functional constructs that have been introduced into C# 3.0. Of course it comes with a very nice syntax.
Let's be more precise. We're talking about LINQ to Objects here, not LINQ.
The implementations of most of the Enumerable extension methods are fairly straightforward.
Query is important, and LINQ to Objects is great. I love it! But, as we'll see with PLINQ and the TPL, the functional programming constructs that enabled LINQ to Objects are capable of much more than that.
I don't see how Volta is relevant to your point.