I agree that in the end exploration will depend more on human-supervised AI then on Elon Musk's vision of a one million-person city on Mars. What would those people do that can't be done by the advanced robots we might have in 50 or 60 years?
Does anyone remember the old 1940s plans to send rockets to the Moon? These ships had large crews with dozens of people because the values that controlled the rockets and the life support system all had to be operated by human hands. Automation has made it so that today we can do unmanned landings even on Mars. The automation will advance over the next 50 to 100 years to the point where the only people we need to send to space are tourists. Tourism will be what drives manned space missions.
In 60 years few people will drive cars on city streets, likewise, there will be no need for human drives in lunar vehicles or pilots in spaceships.