Out of curiosity, is there something one can store that would last 40 years (guesstimate of my remaining lifespan) while still tasting good so that I would actually eat it?
I've had boxes of emergency rations (add hot water to get some rice meal) in our house, but they usually just advertise lasting for just a few years.
I've had some fun trying over-date packaged foods a few years back. Regular store bought stuff. Personal record: a >25y old can of fruit cocktail - still edible. Conclusions:
For dry / packaged goods (dried beans, lentils, pasta, rice, spices, toast, etc) you can basically ignore the best-before date. Sugar (or -syrups, honey) & salt keep indefinitely.
'Wet' stuff, as long as sealed hermetically (like canned goods, shelf-stable drinks etc): similar. Seal broken: all bets are off. Use eyes / nose / texture as indicator, or don't risk it.
Long storage of these isn't a safe-to-eat, but a quality issue. Taste, sometimes texture, and vitamin / nutritional value deteriorates over time. 'Wet' stuff generally faster. Up to a point where you're left with tasteless calories with 0 vitamin content (but still safe to eat!).
Also: say you have 5y worth of food stored. Then you'd need to replace that vast amount of food semi-regularly (like use 1y worth, give away & replace the rest), which is very costly. Or consume everything yourself (FIFO). In which case a 5y's worth store would mean eating -on average- 5y old food. Not to mention the cost/waste if that supply is somehow lost (flooding, housefire, bugs, rodents, whatever).
Imho a 1 month up to 1 or 2y supply is a better compromise. Modest space/$ investment & most stuffs can be eaten within their BB date. But enough for peace of mind or ride out a wave of economic / social mayhem. Add some vitamin pills if you're worried about fresh fruits/veggies remaining available.
I've grown my own food at times. And imho substinence farming is underrated. But as a hedge against catastrophy? No. Do it for fun, do it if you have a large garden & like your independence. Or prefer the organic-everything & knowing where your food comes from.
Otherwise just buy food in bulk & stuff it in cellar (or wherever).
Stuart Ashen (ashens) has a YouTube channel that ventures into trying expired packaged food. In practice, it appears that sugary things do not keep indefinitely, though that might be because the packaging isn't designed to last decades.
I've had boxes of emergency rations (add hot water to get some rice meal) in our house, but they usually just advertise lasting for just a few years.