Do you think this "pinching down on" of the regionals somehow has an endpoint in sight?
Honestly, I have no empirical evidence to back the following up, but here's my WAG based on historical cycle stuff.
I see us in the 2nd major cycle of the airline industry. The "legacies" of today went through all the stuff the "regionals" are going through. They all started out as some regional air service with crappy pay, high death rates and non existent work rules. They grew to national domestic networks that fed our overseas carriers PanAm and TWA. Eventually, jets were invented, and they all upscaled to the jets dropping the smaller markets. Some of the old stalwarts failed, some are still around.
Along the way, the pilots fought for the wages and work rules we look back on with envy and rose colored glasses.
Then the next crop of small airlines started...a "new" industry segment called a "commuter". These small airlines ran prop airplanes on routes from small cities to feed the bigger airlines. --See a trend here?
As far as where the "regionals" go, I say a couple will grow into the next major carriers. Right now, I'd say the odds on favorites are my alma mater, RAH and SkyWest. Anything can change though. As the "original" group of commuters have grown to nationwide domestic network carriers under the auspicious "codeshare" arrangement, a new group of fledgling carriers have grown to replace the 19 seat and 30 seat routes that have been abandoned, witness Great Lakes with the 1900 and Brasilia expansion, Cape Air getting the ATRs and they are openly talking about fleet replacement for the 402s, with their new JetBlue arrangement.
Then you have Colgan....is it a leader of the next generation of high capacity/ high efficiency turboprops, or is it a laggard that will have a bastard one off fleet of Q planes?
I don't see any changes in the evolution of the business, unless there is a marked revolution of the pilots in all the major brand CBAs.
It's always interesting in aviation and these times are no different.