This is usually what happens before a civilization dies. It turns inward in an appeal to address its internal problems, dismissing innovation, exploration, and expansion. And then the civilization simply disappears into irrelevance.
Exactly right. This is why Newt's idea isn't crazy or grandiose, it's exactly the right medicine for an ailing nation. If everyone thought space exploration was more important than frakking welfare for moochers, the nanny state would be history and we would be the first starfaring nation.