I think you're underestimating humanity big time. Ever since we came to be we've pushed limits, broken barriers and achieved the impossible. I think that trend will continue. We came into the 20th century on horseback and left in a space shuttle. What will we achieve in the next few centuries?
I'm not underestimating anything. Remember all the rosy forecasts from the 1950s and 1960s about how we'd be powering around in floating cars and jet packs, and taking the Pan Am clipper to the Moon by now? Didn't happen because the challenges are so great. An autonomous robot that can operate in an almost totally unknown environment millions of miles away from Earth is going to be much, much more complicated.