>>16700693 (OP)The true graypill is that eventually either we upload our minds into robotic bodies or there will be AIs inhabiting robotic bodies. This is likely going to happen in the near future.
Once that leap is achieved a LOT of the space colonization becomes instantly trivial.
You no longer need to search for planets within "habitable zones" or any of that shit. Such robotic bodies can be adapted to survive most conditions and can be modular, replaceable and so on. Planets that would take forever to terraform or ones that would have to be colonized with sealed environments would be free to use as needed with no restrictions.
Travel to other star systems would be as easy as going into sleep mode and instantly awaking on approach. Any minds (AI or otherwise) could be backed up and so on...
Right now the main issue is that we're too fragile and limited by our lifespan (and only a couple of decades of true "mature" and functional operating time) and again, none of that would matter once the leap is taken.
This is why planning for space colonization using today's paradigm and tech is pointless. Whether we like it or not further leaps in robotics/AI and so on would leave that all in the dust.