Why DID we stop short? I was so disappointed, then and now. The Space Shuttle NEVER had the attraction for me that the Apollo program did. Why is it that we got to the moon repeatedly with 1960s technology -- computers that don't hold a candle to the one I'm using now, for instance -- and now we play parking orbit?
It's like a child who takes that big step, learns to swim in that big ocean, but becomes unsure and self-conscious.
Pretty soon he stays on the beach ("It's safer here.") Sure it is, but it's also giving up the stars for a bucket of sand.
By all rights we should already have bases on the moon, and of course an array of radio and visual telescopes on the far side.
We could - with a moderate effort - have sent a manned mission to Mars before the 20th century ended.
Sure there was once more water on Mars.
In fact, some evidence exists for ambient surface water early on, and catastrophic melting of permafrost later, from meteoric impact, perhaps.