Apollo 17 astronauts drove roughly 12 miles in around 8 hours to get to a site and do some science. The curiosity rover's longest drive in a day is around 150 meters. If it drills a rock and encounters some difficulty, it has to wait send a reply home, wait another 4-24 minutes for the message to get there, wait 4-24 minutes for a message to come back before proceeding. It's also obviously unable to conduct repairs on itself or it's tools, or even do something as basic as cleaning the dust from itself.
Robots certainly have the advantage in longevity; curiosity has been operating since 2012 and is still going, but it's like comparing a roomba vs a team of professional cleaners. I think if you asked a planetary scientist if they'd could go back in time and instead of sending curiosity, send a couple of people for six months, they'd do it in a heartbeat.
Think of all the science the robot will get done in the decades of research and engineering necessary to figure out how to get a human there and back to do science without immediately dying.
