Why not just build the Saturn V again? It's proven (worked every time it was flown - zero failures), uses low cost fuel (liquid oxygen and high grade kerosene) and can put 200,000 pounds plus into low earth orbit. Yet I never see this option discussed. What am I missing?
Several reasons, actually. The most important is that the Saturn V was not exactly designed to be a production rocket. It was an extreme piece of experimental equipment from the days before we started pissing money needed for space development into the welfare rathole. It was not designed to be mass produced (even for limited production runs).
If we really want to get mass to orbit prices down, we need to develop a reliable reusable huge modular engine which can be strapped onto whatever tank / payload combination desired. We should stop thinking of building single design rockets, and instead concentrate on developing OEM style mix and match components. This is where the industry will eventually go. The cargo container ship is a valid anology for the eventual future.
However the cargo container ship idea breaks down for modern economics. Currently, the only traffic into space is up, and then the only economic traffic is relatively small satelites. A super-heavy lifter would help the International Space Station a lot, but the ISS only consumes money (sounds a lot like the U.N.). Until there is a profit source for sending up huge payloads, there won't be much real heavy lifter development. The only current possible market is the ISS (not profitable) and possible space based weaponry (which also hardly profitable when you think about it).
There will be moon colonies before we ever come up with a mass produced cheap heavy lifter, and we will never have moon colonies so long as there are hungry welfare mouths down here demanding the development dollars got into them instead.