This is destruction on a scale that has not been seen in the likes of civilization outside the bronze age collapse.

The fact is there is going to be no one coming to help replace burned up hoes and shovels.

Threads and the Day after weren't a snapshot of one single city - they were a snapshot of what would be happening everywhere else at the same time.

If the risk was a war involving bombs like Little Boy then there wouldn't be much to worry about beyond localised disaster. The issue is the weapons that are 2-3 orders of magnitude more powerful.

And you're referring to Germany, which that took casualties approaching something close to 10% of its population during WWII - so you're eyeballing a scenario where a country just lost 10% [0] of its population and saying it looks fine to you. That seems a weak argument that the damage is nothing we need to worry about. We can argue over whether nukes are going to kill 100%, 50%, 10%, etc of the population but frankly I don't see where you would want to go with that.

[0] Not from bombing, obviously, but the situation you're talking about is nonetheless one where Germany just suffered massive losses and you're saying you can't see that in a photograph after the cities were rebuilt so no worries if something worse happens.