Are Americans too poor to dream, or getting poor because we refuse to dream?

This question grew out of my listening to Neal DeGrasse Tyson’s brief video about Americans having stopped dreaming of exploration back at the end of the 1970s. His talk reminded me of this ad from NBC’s Lean Forward campaign. Are Americans giving up the future in favor of present-tense greed? Are Americans willing to kill the goose that laid the golden egg in hopes of getting all the gold right now? America, with just 5% of the world’s population, still has the largest economy on Earth. Are we really too poor to dream, or are we getting poor because we’ve started listening to those who refuse to dream, those who want all the pie for themselves, and want it right now?