A very realistic scenario, back in 1988 CAAC Airlines was split into the big three, being Air China, China Southern and China Eastern. Each of them was headquartered in a different part of the country. Greater Bay would make the big four, and whilst it’s a bit close to China Southern in Guangzhou, there is probably enough air traffic in that region to support two major airlines.
All the profits stay within China, Beijing tightens its grip on HKG and one of the last relics of the colonial era is gone.