We've been there already. There's nothing there. Certainly not anything cost effective to bring back. This program has been nothing but grandstanding bullshit since they started it. Yeah, we got Velcro out of it, but the novelty is over and everyone's gone back to tying their shoes and buckling their watchbands.
Can our technology, and our own bodies, handle working & living away from Earth? We want to get to Mars, but we haven't been to the moon in years. We can handle being on the ISS, but that is right there in comparison to pretty much anything else.
Many of these questions can be answered by putting a "long term" base on the moon (and maybe something in Lunar Orbit). I see it much akin to the young person who wants to move out. Sure, they can live in the granny flat or basement (which would be the ISS). But before we spend a fortune getting you a house a few States away (Mars), prove to me that you're capable of living in an apartment across town (the moon). Either way, we are going to be paying for it (financially, but hopefully not with human lives), so having a degree of confidence would be nice before we start racking up those costs.
Besides which, data has value. We've learned much about ourselves in micro-gravity. Seeing how we respond to less than earth gravity, but greater than micro-gravity would be good.
~Jeordam
Saving the Princess, Humanity, or the World-Entire since 1985