It's like that was because it wouldn't be good to have customers see "expired" food on your shelves. As a customer, I wouldn't buy food which has gone past the expiration date. Sure, it could be fine to consume but I'd rather purchase food on that's well ahead of the expiration date. Especially since I may not cook/eat the food until a day or so later.
But some interesting economics starts becoming apparent when packaged food products approach the last 1/3rd or 1/4th of their shelf life. For e.g.
- near-expiry food products being exported from developed countries to developing ones (where they still command a premium over local products). I've found entire shelves of imported food products just months away from expiry (out of a total shelf life of, say, 2 years)
- re-badging of expiry dates/lots by unscrupulous importers
- 2 for 1 offers in supermarkets to liquidate near-expiry stock
Here in the UK it's illegal to sell food after the "use by" date and every so often someone gets in trouble for it. ("Best before" dates, on the other hand, are advisory.)
