Done by people who either never had to go without electricity for more than 24 hours due to environmental conditions.
OR WORSE - people who went through something like that without learning anything.
Every single thing made by man has multiple fail-safes built in, which have been either designed from the start OR have been evolved into the object through generations of use.
Only it is so obvious to us that those parts should be there, we don't even see them now.
A simple thing like a container for carrying water with you, only couple of decade ago didn't have a built in system which prevents accidental opening and spilling of the contents.
A screw-on cap.
Not so long ago we used cork plugs. And breakable bottles.
Evolution and additional fail-safes.
We've been building civilizations about as long as we've been making knives or bottles.
There are fail-safes upon fail-safes built in.
From education which creates people who know how to fix and make and work things, to society control and guide systems like morality, various allegiances and duties, laws... even religion.
And that's not taking in account simple things like building infrastructure with backups, shielding and hardening - particularly the things that are build to function 24/7, 366 days a year, for at least 40-50 years.
Humans build things that WORK.
Because that is their primary function we build them for. Followed closely by "it needs to keep on working".
Built-in obsolescence had to be invented so we'd keep on spending money.
So we'd have an economy that "keeps on working" once we got it to work.