The other insight Bezos had about books was that the extent of the market was limited by a physical constraint in how big a store could get. It was a perfect product to exploit unmet demand for long tail titles. Groceries don't seem to suffer this problem to such a degree. Most of what people want to eat is available in local stores.
Is that actually true? I remember my dad always complaining that the supermarket had stopped carrying his favorite snacks & meals. And I can think of a few of my childhood favorite foods that are only available in New England, and I very much miss them now that I'm out in California. People do home-cooked meals all the time that combine ingredients in ways that store-bought food doesn't have, and they have family recipes handed down through generations for things that can't be bought in stores.
I suspect that most of what people want to eat is in local stores only because their wants are constrained by what's available. Typically, people don't continue to want what they can't have for long periods of time, because it just makes them unhappy. I suspect that if you solved the perishability problem, there'd be a huge untapped market for long-tail foods.
