perhaps the more relevant question to ask is how DL is the only legacy carrier that wasn't one of the "chosen instruments" of US aviation either as one of the big 4 domestic airlines - of which only AA and UA survive - or Pan Am internationally and yet DL has become what it has.
DL's DNA has long been built on the idea that success comes from running an outstanding business and aggressively winning business including from other other airlines. DL has not only not been afraid of vigorously competing in the top markets of the world but has repeatedly sought it out, a trait that is not the norm in a semi-oligopolistic industry, which the airline industry is.
DL has clearly merged and acquired a number of airlines but it could not have done that and grown on its own if it didn't run its own business very well.
Whether I talk about it on here or now will not change DL's DNA.
It also won't change that other airlines have not operated on the same competitive basis as DL has done.
Consumers know what good competition does for price and choice, regardless of the industry.
The lawsuit being discussed here is because there are people who believe both will be hurt by the AA/US merger. The government's handling of N. Texas aviation is resulting in the same limitations on competition to consumer detriment.
DL happens to be on the side of aggressive competition which is also what consumers want. DL has won in the marketplace because it has embraced aggressive competition.
That reality affects every employee in the airline industry.