It's not a bad thing that shops aren't stocking ridiculously huge quantities of things. I always used to think it was awful to go to the shops the day after Christmas and there were huge piles of Christmas stuff everywhere being sold off at half price or less which would ultimately be waste if not sold. Massive waste of resources and incurring losses for the businesses. And of course, people buying stuff for next to nothing would probably dump it themselves in due course rather than keeping it for future years.
Shops would have been ordering their Christmas stocks months ago, and of course, most comes from the Far East and transported by container ships, so there's no scope for any "last minute" orders to replenish unexpectedly popular items.
Shops don't keep stock from one year to another any more as they don't have long term stock rooms, and it'd be more expensive to transport it and store in warehouses for a year, so hence they sell it off cheap or just dump it in the skip.
Of course, in the old days, shops did have stock rooms, often on the top floor (attic) above the shop or the basement/cellar, but modern stores have neither. My father was a High Street chain store manager in the 70s and it was always exciting to go up to the attic rooms where all the seasonal stock was stored - Christmas, Summer, Easter - it was all there, and brought down again when the time came, to add in with the new deliveries. No waste, no stupid discounts, just room to keep stuff. It was fun playing with Christmas stuff in Summer!