The neural network approach should be able to crush any NP-hard problem into an easy problem for the subset of real world examples, although not for all possible examples.

When you say "The neural network approach"... you are effectively refining the problem space into something smaller based on the data that you are training the NN on.

(Note: I'm speaking vaguley, on the same vague level as your comment. I can be more precise as to what my indications indicate)