If disks are failing and floodwaters are rising, I absolutely hope I have offsite backups!
The need to actually have that offsite backup being online makes them rather unlikely. Like setting up your offsite in middle of desert and trying to make parts there yourself. Fun times...
Presently it does not appear that the current cataclysms predicted for Earth in the short term (500 years) will result in destruction of the biosphere or even human extinction.
Early humans and their ancestors have experienced two major population bottlenecks in the past. We may well see a third relatively shortly, but that is very different from extinction.
You're using a linear model for exponential processes.
Which processes? When, why, and how will they become exponential?