[tkahnoski]

Even a hybrid mission with humans in orbit doesn't make sense. You have to bring less fuel for landing/take-off from Mars. But for that same cost you could send way more robotic workers and just deal with speed of light/delays (3-20 minutes).

If there was significant uncertainty in what resources needed to be deployed to where then I could see a benefit to having an onboard team of humans who could assemble workers or payloads on the fly from orbit. However this would be a big shift from current mindset of designing robots for exact problem/solutions with precise payloads to instead having an excess of resources on board.

If the perspective shifted to "we're colonizing Mars so every ounce of metal in orbit will get used at some point" this is less of a concern.