These barriers look pretty solid to me. Not that my opinion matters, but I wouldn't give any more money to NASA until it demonstrates the ability to find its gold-plated ass with both hand faster than in a decade. In more formal terms, it's not that NASA is just inefficient, I wonder whether it's capable any more...
Given the obvious fact of ongoing space exploration (Curiosity being the most prominent), NASA is obviously capable to some degree. Current missions demonstrate success and competence in areas that few other organizations have even attempted.
In other words, the machine is still running- put money in one end, and a space program comes out the other. If that's not a good enough ROI for you, that's one thing. But I think a group of people that are running daily experiments in their Martian science laboratory qualify as functional.
"The White House Office of Science and Technology Policy is planning ahead — way ahead. The agency wants you to email ideas for how "the Administration, the private sector, philanthropists, the research community and storytellers" can develop "massless" space exploration and a robust civilization beyond Earth."
This is beautiful.
"We are running out of adventures [...] the mountains have all been climbed, the continents explored, and the romance of sailing away on a tall ship to undiscovered islands is no more. What will fire the imaginations of the next generation?"
http://io9.com/white-house-seeks-advice-on-bootstrapping-a-solar-syst-1647619795