In my view it's an economic issue, not a technological one. If as much money had been spent on space travel as has been spent on computers in the last fifty years then we'd have cities on the moon, no problem. But "we" didn't, because it made no economic sense -- or at least there's a vast technological gulf we need to breach before it starts to make economic sense. Money to develop computers came from the pockets of individuals and companies because they wanted computers -- money for space travel came from government departments for reasons unclear even to themselves.

If progress in space travel seems slow, remember that almost all of the money going into it is spent by a single organisation whose budget is less than 10% of Apple's revenue.