[rwmj]

You can make soap at home, a factory anywhere can trivially make it. And face masks are paper plus string, again hardly difficult to manufacture in any city in 2020. (In the UK most paper was made centrally in 1918, I happen to know this because I live near the site of the former paper mills - https://www.thepapertrail.org.uk/).

[varjag]

Look, I have a lathe at home and can make an engine if I want to, thing is other people can't because they never were interested in that. And I used the simplest things possible as examples.

Realistically, where would you start with these in a typical deindustrialized town today? "A factory" is a poor answer, some towns have none really, and factories are not interchangeable anyway.

[rwmj]

There are small factories - everything from workshops to industrial estates - all over the place. If anything it's much better now because CNC machines and lathes are cheap, widely available and very versatile.

[throwanem]

Yes, they're cheap and widely available. That's because we import them from China.

If your plan for resilience against a long-term disruption of global trade has a critical dependency on global trade, you may need to rethink it somewhat.