Your first point intrigues me. Could you possibly elaborate on how the "reprocessing" of food works and what that process entails?

I imagine it's similar to any other processed food. Take initial food, change it into another form, most likely not even related.

Dry pasta is eternal as long as its kept dry, but can't be legally sold that way. Ditto plain white rice. Non white rice goes rancid in a couple months.

Aged "many years" cheese is normal (for some hard cheeses), but its only allowed to age a couple months in a fridge.

Potato chips if sealed from air won't go rancid.

Chocolate is eternal unless contaminated and even if its bloomed it can be remelted and re-tempered.

Honey is also eternal. Ditto syrups. And yes its illegal to sell food without an expiration date so even honey has an expiration date laughably. Crystallized honey can be fixed by 20 minutes of heating.

Salt has an expiration date. No kidding. For that pink Himalayan salt (or more likely fake made with food coloring) its 15 or 20 years I don't remember which.

I had to look it up... Himalayan salt is a Cambrian era deposit. 20 years seems a little short.

A MRO tech at a potato chip factory told me the chip bags are filled with nitrogen. So maybe they are free of oxygen inside.

I think many nonperishables with expiration dates (distilled water etc.) have to do with degradation of the container.