Here is a question worth taking seriously.
What makes something a luxury?
The obvious answer is quality. Luxury things are better made, better materials, better performance.
That answer is mostly wrong, and grocery stores prove it better than almost any other category.
Because a tomato is a tomato. There is a genuine quality range, and it is narrower than the price range by an enormous margin.
A premium grocery store charging considerably more than a conventional one is not selling a tomato that is proportionally better. Nothing about a tomato can be that much better.
So what is being sold?
A California chain built a business answering that question, and the answer is genuinely useful to understand, because the same mechanism operates on you in categories where the money is much larger than groceries.