To use your analogy, the gas station owner would have to drive by every competitor in their city, as well as all the neighboring cities, as well visit every similar populated city in their country to get the same information. A service that tells sellers what they should charge is what I don't like. I seriously expect in many situations, these "price aggregators" are probably corporate subsidiaries of the market leaders.
They’d have to do that iff someone would consider buying gas 50 or 500 miles away as a reasonable substitute for buying gas from them.
> A service that tells sellers what they should charge is what I don't like.
Is it only the “tells sellers what they should charge” part that you specifically object to (the conditional messaging) or do you also object to the lesser “tells sellers what others are charging”?
> only the “tells sellers what they should charge” part
that, and when they inform the seller they use emotionally loaded language implying "if they are not the market leader, they are leaving money on the table, like a fool." Yes, the service consumer has to be a little manipulable for such mechanisms to work, but they do, nearly all the time.
