Comment on Apollo Moon Landing Hoax – Photographic Evidence by jfb.
This has only been answered a dozen times already.
Short answer: $$$$$$$. That’s the primary reason. The Apollo program cost something like $180 bn in 2010 dollars. While that’s a drop in the bucket relative to the entire Federal budget, it’s more than Congress is willing to pay for something that isn’t related to defense or social programs. The ISS will continue to suck up all manned spaceflight dollars until it’s deorbited.
Other reasons: the manned program is a mess. NASA’s been jerked around so many different directions over the last 40 years that it has no direction or vision anymore. The manned program has no mission other than to perpetuate itself.
I don’t expect the new Space Launch System to fly, at least not beyond the prototype stage (similar to the Ares 1X from the now-defunct Constellation program). It exists solely to preserve jobs in the legacy Shuttle manufacturing sector. SpaceX’s Falcon Heavy won’t be able to do the job, at least not in a single launch. And somebody has to build the spacecraft to get there and back.
All that aside, manned spaceflight isn’t easy; you have to shift a lot of mass, meaning big rockets with powerful engines, meaning lots of $$$$$$. You have to build robust spacecraft with lots of redundancy.
And there’s just no compelling reason to send people to the Moon (or anywhere else, frankly). We could learn much so much more about the lunar surface with far less effort using unmanned systems, especially considering the advances in the last 40 years. Look at the Mars exploration program for an example of how much can be accomplished using unmanned systems, both on the surface and in orbit.