Our long term survival depends on some of us getting off this rock. Short term thinkers may not care.
I think we will get there much faster the sooner we develop and perfect the technology...robotics, automation, and AI. We should already be sending and testing that technology to the Moon and Mars. Human habitability is very expensive, and to the extent that it undercuts those hardware developments, it is counterproductive to the long term goal.
Using only unmanned spacecraft will never get us off this rock in numbers to last and sustain elsewhere.
We'll have to establish a colony before Islam eventually ends up taking over the world.