The 'frantic shopping' seemed to have disappeared in some stores some time ago. I went to Waitrose in Ipswich at 0755 last Thursday (during the oldies' hour) and there was only a fairly short queue outside. When I left at just after 9, there was no queue at all (and hardly anyone in the store).
I suppose that, once people have completely filled their cupboards, fridges and freezers with food, it finally dawns on them that they don't actually need to go shopping for a while!