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.
The point of Volta is this context is twofold
1 - It is possible to use C#/VB/_
2 - It is possible to use the special LINQ syntax(es)
But the new constructs enable other things than LINQ as they should. They are part of a general purpose language after all. TPL does look like a very good mid-term solution to parallelism. Long-term, who knows.