Also, the crash program of the 60's was as much about geopolitical machinations as a science. It was an "us against them thing", and nearly everybody was behind it.
Now, there is nowhere near that level of competition, There's no real sense of national pride. Nobody gives a damn about space, except for the military, who must dominate it, and the scientists, who want to understand and explore it. Your average person and the politicians who get their votes just don't care, because it has no percieved value. Who's gonna vote for a politician "squandering" billions ( remember when that was big number? lol?) on "worthless" projects such as Orion and the dozens of lesser known probes when they can't afford to see a doctor. You wait and see Nasa's budget after national healthcare gets passed. I mean, it'll be nice for me to finally be able to see a Doctor, but it'll basically be a budget so low nothing at all will get done. I bet it would cost a quarter billion dollars to do absolutely nothing except keep the lights on.
There's no way we'll explore the solar system without a multinational effort. It's just too expensive. With all the countries with the highest level of technology suspicious and all but looking down the barrel of a rifle at each other, it makes it that much harder. I don't know if it's ever going to be done. I'll be lucky to see a human boot on Mars before my time on Earth comes to an end.
It's just sad for a kid who grew up with the Apollo program and raised on Star Trek ( sniffle).