I'm blaming government. Nasa is a part of government.
Nasa has spent over $100 billion on a 400 ton solar powered space staion with room for 6. That's enough money to build 20 100,000 ton nuclear power aircraft carriers, or around 50 nuclear powered submarines. Nasa has spent tens of billions of dollars developing rockets that got no farther than power point presentations. Space is nowhere near as expensive as what Nasa has made it out to be.
Regardless of who exactly is to blame, the way Nasa is organized has made it impossible to carry out any sort of strategic long range goals for manned settlement of space. Funneling money to certain congressional districts is their sole reason for existing.