Until people start buying additional fridges and freezers, or building additional sheds, to store all their hoarded stuff. The scary thing is, people *will* do that. Some people are utterly obsessed by it.
The threshold of how much is reasonable varies from one family to another. A large family with a lot of children will get through several bottles of milk and more bog rolls than a couple of people. It is fine to say "if you genuinely need more stuff, go shopping more often"... except that trying to arrange a supermarket delivery slot is a major problem if you can't go out because the government advises/orders you not to. My wife is managing to get Tesco delivery slots as long as they are almost a fortnight into the future, but despite checking every night at midnight when they announce the slots for the next delivery date in the future, she's never seen *any* free Sainsbury's slots. I wonder whether some people have got automated systems which grab every slot as soon as another day's-worth of slots is released, and then auction them at an inflated price.