Give NASA a break. It's not completely their fault. Their recent budget cuts has been a killer. I would say that Lockheed Martin hasn't done anything because they don't have enough of an incentive to bother, but the rumors go that they have been building trans-atmospheric craft for the U.S. Air Force in secret. Craft that are super fast, and super secret.
Pffft, NASA has not impressed me for years. And considering they have the damned Brookings Report, which I hate with passion, I have no respect for NASA to begin with.