A few important differences between the First Cylon War and the second:
It is not a nuclear holocaust. Think the London Blitz not Hiroshima. There are war-torn areas, but elsewhere life goes on.
The Colonial Forces are very new. Up till a few months ago, each colony has been fighting the Cylons independently with its own army/fleet. This is the first time people from different colonies have come together in the same unit.
The tech level before the war was more on par with modern levels with things like smartphones, VR, AI assistants, etc. Much of that tech now is vulnerable to Cylon network intrusion, but it's still out there.