Over here in Europe, many grocery store chains (e.g. SPAR, Billa) have stores in the arrivals level of airports and everyone of them are packed:
- passengers buying food to carry on board;
- employees shopping;
- Airbnb clients (that's me!)
IMO, they face fewer restrictions on operating hours than their downtown locations. Prices are comparable. I have personally witnessed this in TXL & VIE. An exciting development!