Some of these things you could make yourself or were commonly self-made instead of buying, but that, too, requires planning and discipline.
I'm a bit shocked that some people think of medieval life as something like Elbonia in Dilbert comics. Heck, I even find the middle ages a pretty boring time in human history, but I know enough to understand that it wasn't as simple as "everyone lived in the mud and ate mud".
These are very important things and most of them take place on longer or much longer timescales than a few months. Early humans weren't monkeys, and after they had left the tropics, they couldn't survive without planning because getting food is difficult in winter.
Decreasingly so, thanks to climate change. The increase in temp isn't the problem. It's that climate change increases the frequency of outlier temperatures on a seasonable basis. Crops don't just fail if the average is too hot. They fail if there are too many hot/cold days in a growing season. And that is the unpredictable thing we're going to be running into in the future. Certainly while we're all alive. It's already happening.
Latin American climate refugees have been fleeing north precisely because of climate change decreasing crop yields.
