I've asked for a list of institutions from which proposals have come. At the very least, I'd like to compare a current year with a benchmark year say, a decade ago.
My premise is that the success of proposals is limited by the fact that we have “too many mouths to feed.” We are producing 50% more PhDs per year than 10 years ago (AIP figures). Many of these people have been staying in the field because soft money has made this possible. Also, many smaller schools now have research astronomers who can compete for funding with the traditional more powerful institutions. Consider the UC system alone: 20 years ago, there were not many first-rate astronomers at Irvine, Davis, or Riverside. But there are now, in large part because there are resources to support their work (Keck, specifically). I believe that the distribution of institutions who are proposing to NASA R&A and NSF would demonstrate this. We might be able to get some numbers from maybe the AAS on number of people in faculty positions and number of postdocs in the AAS, that may demonstrate it as well.
Hashima Hasan thinks there might be a problem: NASA may not be allowed to release any information on failed proposals. If not, we probably just look at the distribution of awards by institution, which might be actually more relevant.