The food companies probably over estimate the dates to avoid lawsuits and prosecution by the government.
Someone call Nadar. lol
There isn’t much to avoid from lawsuits on canned food, because canned food is always safe to eat, as long as the can is intact.
What is inside of the can is sterile, the ‘best by’ date is just a guaranteed date that the product will remain perfect, and is more likely meant to generate people throwing it away and buying more.
Some things do better than others, for example I recommend using canned pasta dishes like ravioli and chicken noodle soup within a year or two of the date, because the pasta doesn’t taste as good after a few years, but canned chili, tuna, spam, corn, peas, sardines, corned beef, mixed vegetables, etc, last for years and years past the dates.