Thinking: the problem with space elevators and human passengers is one of safety. It takes a long time to get something high in orbit, and it’s a hell of a high gravity tax to seat all of those people comfortably and safely. So, you knock ’em out, stack ’em like cordwood, and stick ’em in a lead-lined box for the long ride up.

So, would a civilization that’s capable of that have any technical limitations? If you can kick ten thousand fishsticks into space at one go, why can’t you shrink ’em? Upload ’em? Crack time-space on the ground and let ’em slip through to Dimensions Beyond?

Is it a moral issue? Do the Luddites keep you from monkeying with genes and quarks? Or are there technical limitations that we just can’t crack? If you had an army of hungry mouths who were willing to do any crap job, would you bother with AIs and the like? Why create new problems when human nature is relatively unchanged?