Correction: If dinosaurs had a NEO program, they'd still be here.
and humans currently do not have much of a NEO program either.
The current debate in the NEO community is as to exactly how stupid humans are.
Most believe that the most likely scenario is that another "small" Tunguska class impact will occur, and then humans will do something. I am not too sure about this, because if the impact is mid-sized, the loss of a nation state may be enough of a disruption to prevent action being taken after the impact.
As for the US role, while NASA spends large amounts to appease the Mars fantasists, the US NEO program is in disarray.
EP