Astronauts covered a lot of distance but they didn't do a lot of science. Though to be fair, they weren't there to do science. They were there to plant flags, take selfies, and maybe bring back some souvenirs so that science could be done back on earth. They didn't even send up a scientist until that last mission.
The rover there was primarily to establish ownership. Having done that, they stopped.
A team of humans might improve the efficiency of the robots, by repairing them faster and doing some other work locally. But for the same cost you could send up an awful lot of robots.
Name a robotic mission that has brought back more than 200 pounds of “souvenirs” from another world.
Eventually robotic missions will get there, but more often than not they will be as a vanguard for human exploration and settlement, because even though I put aside human motivation for arguments sake, in the real world humans have a deep desire to explore that cannot be placated with data from a probe.
I am willing to wager a human mission will not receive the same pushback, even if it's 10x the price.
The human angle here cannot be ignored.
The Apollo 17 rover covered 20 miles in 4 hours.
Ego and the human spirit aside, humans are better at exploring than robots, even with 50 years of advances in robotics.