Well, Huebner uses two metrics -- patents, and a textbook -- which may not be measuring very much. Patents are just the commercial property-right to an invention, but lots of innovations (in art, culture, programming, etc.) never show up in the patent office.
What *is* stagnating and being cut back, though, is the US university system, its once world-class labs and research facilities are going on the chopping block. Per capita numbers of US PhD students have been stable or slight decline for 30 years, NIH funding is being slashed, foreigners are starting to go to school at home instead of coming to the US. FOI, an Intel-supported thinktank, has some numbers here:
www.futureofinnovation.org/PDF/Benchmarks.pdf
-- DRR