Either the airport taxis are different
This.
Over many years, a repeated conversation with what I would consider the more professional, cleaner, well skilled drivers, is that they would rather lots of short fares, than hang around at the airport for a couple of hours waiting for a big fare . There seems to be a certain type that will go and wait at the airport, and another that will take on lots of short fares within a suburb or group of suburbs.
Also are your fares hailed at the rank, or booked over phone or app via a specific taxi service provider?