Colin W Kingsbury wrote:

In fact, the monopoly power (or lack thereof) that certain carriers have
over hubs is probably the main reason they are still surviving. It's
probably the only place in their operations that consistently makes money.

Au contraire. It is exactly because the legay carriers have been able to
and have milked customers in areas of non competition (their hubs) that
they not only developped high costs, but also left the door wide open
for the first low cost carrier to enter that city and really hurt the airline.

The legacy carriers abused yield management for short term gains back
then, but they are now paying the big bucks for it.

Had the legacy carrier not milked customers (in particular business
customers) just because they could, they would have had much greater
incentive to lower their costs so that they could be more profitable
carrying more passengers with a lwer yield, instead of relying on fewer
pax paying exhorbitant fees.