The beacons in the store are pretty dumb, so they can be cheap (on the order of a few dollars each) and plentiful, moving the real logic of tracking to the app.

The beacons in the store are pretty dumb, so they can be cheap (on the order of a few dollars each) and plentiful, moving the real logic of tracking to the app. You're correct in that it could be reversed and the BLE radios in the store could track the phones instead, but then they'd need far more intelligence and network connectivity, which would make them more expensive and in turn they'd be fewer of them deployed. Source: spent the last few years writing code for wireless devices, including BLE beacons.