**eburacum45 **really nailed it.
There’s a big difference between “we” as in current society versus “we” as in a comparative handful of *de facto *colonists.
And between “survive” as in “live out our ordinary prosaic lives in the midst of a plentiful natural ecosystem” versus “everyone is locked in a continual struggle to maintain our little band and its totally artificial life support systems against failures, continuous wearing out, and an ever-encroaching utterly hostile and unsurvivable natural environment.”
And between “a while” as in “millennia upon millennia into the indefinite future” versus “your young kids might live to reproduce, but their kids mostly won’t.”
The very tech that could, given enough warning, be deployed to keep a few hundred thousand humans alive on the otherwise dead Earth would be far more complex than that few humans could maintain into the indefinite future.
Posit us having a cohort of intelligent self-replicating robots that “live” on electricity and we’d stand a chance. Current or near future tech? Forget it, at least over a span of, say, 75+ years.