Comment 26 by I Deny :

You have again put personal expectations of scientists and political issues in the same basket. Regress in space flight and transportation has to do with political and economic issues more than anything else. It's hard to argue that it's the science that's holding us back from further space exploration.

Yes, to an extent, I agree it's political i.e. to do with cost. Bush did want to return to the Moon, but didn't want to spend any extra money on it. But it's also to do with science: if there were breakthroughs with fusion or solar or scramjets or engineering lightweight metallurgy or some other exotic fuel or energy source and the cost of travel would come down, then the political decisions would be easier.

I'm not saying it's scientists' fault. I'm saying all the low-hanging fruit has been picked and the science that remains is getting exponentially harder.

Einstein was able to solve several fundamental problems alone in his spare time while holding down a full time office job. Now you need industrial scale facilities like CERN and that take 20 years to build and thousands of scientists/engineers and billions of dollars, and they still can't find anything. The problems are just so much harder, therefore the pace of discovery is slowing, not accelerating.