Maybe because I live near Boston and have seen many airlines enter and leave our "end point" market, I can't get too worked up over Skybus becoming Skybust. We've had Allegiant try and fail in Worcester, Pan AM fail twice at Pease, Eastern go poof, USAir cut most of the former Piedmont flights after acquisition, Delta forget that it's legacy here (Northeast Airlines merger) is as a Florida carrier, etc.
It's great while it lasts and I took advantage of Skybus to fly a daughter who goes to college near Greensboro back and forth for $50 to $60 each way on average.
I'm a loyal flyer like some of you who posted on this thread (2 million miler on Delta, 1 million miler on United), but also realize you don't get the perks you used to on the legacy carriers. Regional jets have greatly reduced the upgrade chances on the shorter flights and the fees on the supposedly "free" travel perks have been creeping in.
As CarolA said and I paraphrase - rich and poor people can be cheap when it comes to flying. I'm definitely cheap, but also realize you can't get something for nothing for long without changes happening that you may not like