Well part of the problem is we have cut back NASA’s budget so much that it’s a joke of it’s former self. Some things you should just fund because the payoff (science in this case) is worth WAY more than what you pay for it.
Looks like the budget has been pretty consistent to me. Link
What we have now that we didn't have 45 years ago is a commercial space industry. We have private companies delivering supplies to the ISS. We have private companies working on a capsule system to get astronauts up to the ISS. Is there anyone here who honestly believes that the private companies won't accomplish all that better, faster, and more cost effectively than NASA ever could?