AR, my list is a few short of yours but I did fly on AirTran last week. Yes, they were bought by Southwest but are still operating as AirTran.
Many of those you mention are still in existence but as part of larger airlines. Although Piedmont and PSA have been merged with Agony Airlines (Allegheny) to form US Air, you can still see PSA (and I believe Piedmont) flights; sort of like United Express or other regional carrier.
The one on the list I really miss is Eastern. When I was flying frequently between Washington and Boston and Washington and Jacksonville, they treated me well. First airline I ever flew first class, first airline I ever flew on international frequent flyer ticket. OnePass with Peoples Express, New York Air, Continental, and Eastern was my favorite frequent flyer program for a number of years.