Growing up, canned food was opened by using a hand-operated (or automatic, if you were rich) "tincan opener". It was a pain to get the damn thing open, and when you did, you were lucky if you didn't cut yourself in the thumb on the sharp edges and fiddling with the little metallic thing with a razor-sharp cutting edge.
Nowadays, really just in the last few years, all the tincans I see have these little "soda can" opening things which require no external tools and opens the whole lid very easily.
"Classic"/traditional tincans are said to hold up a very long time if stored properly. Maybe hundreds of years, possibly?
What I wonder is if the easiness in opening comes with a price for the modern tincans, namely by cutting its "edible until" date closer to when it was manufactered? Maybe they are even deliberately designed such, so that people are unable to "stack up" on emergency food and keep having to buy new tincans as the olds' contents become rotten and inedible?
On the other hand, I remember eating slightly expired cans of various food, sealed with the classic method, and they were absolutely disgusting when opened... But maybe I was just unlucky?