Bizarre. Have you considered writing to corporate about that store?
If, honestly and truly, they can’t sell merchandise fast enough to be worth keeping it on the shelf, then they should at least change their business model to match the reality. Make it so people could call the day before and order their groceries, then have their order waiting when they come pick it up. Sort of like a drop off point for Amazon Pantry. They could even work with local producers for fresh milk, eggs, and produce.
For canned and dry goods, Amazon Pantry might be worth looking into anyway.
HEB headquarters has been notified time and time again. They don’t care. We’ve had one grocery in town forever and it used to be really good for a little store. They enlarged it many years ago but it now seems to have less than when it was little. They hassle you about about coupons (not that the newspaper carries them) and if there’s a national coupon, they’ll take the product off the shelf. Weird.