Sure, a bunch of small/desperate retailers will do this in the short term, but the small handful that will still be around in 5-10 years know that owning the direct relationship with the customer is non-negotiable.
Amazon-level supply chain management and logistics as a service/consultancy.
Amazon started doing grocery delivery in the Sacramento area this year and I haven't touched Safeway again since.
With the Whole Foods purchase I cannot wait for them to completely change how I buy food.
Do you comparison shop at different supermarkets to figure out what the highest quality food is for the lowest price?
If you are like me you did that one or two times when you moved to a new area, but then stick to buying everything from the same store which I thought had the best quality food for the best price in general. The relationship that I have with that grocery store keeps me from shopping around prices at other locations.
No, of course not. That's what the weekly newspaper flyers are for. On the other hand if one is relatively well off, then the strategy you propose of picking a store that seems like an overall good value and sticking to it may make more sense than spending valuable time poring over grocery store flyers and making trips to multiple stores.
This difference in behavior (combined with coupon clipping) is pretty much the quintessential example of how retailers can implement price discrimination - i.e. charging higher prices to those with a greater income or greater willingness to spend.
Could be that Instacart does the same thing. Providing value and supply chain for smaller stores.