Compromise?
Perhaps future robotic missions could be designed so they exploit a manned component. For example, very large robotic space probes could be assembled from modular components at the space station, by human crews. This would not only allow more ambitious missions using existing launch vehicles, but be able to used shared generic hardware and provide training and experience for ISS crews and allow them to earn their keep. It's an infrastructure we're going to need eventually anyway, and it would help justify the cost of maintaining manned orbital facilities.
I'm not in favor of eliminating a manned presence in space, just making it more cost-effective. The market for perfect ball bearings has turned out to be somewhat limited.