Hub transfer traffic is a bonus, a luxury which should only be pursued if the cost of doing so makes economic sense.
Only partly true.
Transfer traffic at a hub might be a bonus where it improves the profitability of some routes, but it makes other routes viable that wouldn't otherwise operate at all.
Besides, as I've said before, it's quite difficult to stop people getting off one flight and onto another at a hub if it makes their journey possible/easier, short of frog-marching all arriving passengers onto the Tube or Hex.
