The existential crisis part for me is that no-one (or not enough people) have the skills or knowledge required to do these things. Getting people to work together only works if some people have those skills to begin with.

I also wasn't putting the focus is on cooking, the ability to hunt/gather/grow enough food and keep yourself warm are far more important.

And you are far more optimistic about people than me if you think people working together is the likely scenario here.

>the ability to hunt/gather/grow enough food and keep yourself warm are far more important

These are very important when you're alone. Like deep in the woods with a tiny group maybe.

The kinds of problems you'll actually see are something going bad and there being a lot of people around trying to survive on ever decreasing resources. A single person out of 100 can teach people how to cook, or hunt, or grow crops.

If things are that bad then there is nearly a zero percent change that any of those, other than maybe clean water, are going to be your biggest issue. People that do form groups and don't care about committing acts of violence are going to take everything you have and leave you for dead if not just outright kill you. You will have to have a big enough group to defend your holdings 24/7 with the ability to take some losses.

Simply put there is not enough room on the planet for hunter gathers and 8 billion people. That number has to fall down to the 1 billion or so range pretty quickly, like we saw around the 1900s.