Because everyone is not losing as much money- a true example of capitalist survival of the fittest.
Not that I won't be sorry, I'v'e flown a million miles on Delta, at least that's what is says on the card they just sent me.
The airlines that are on the bubble will sure leave some gaps if they fail (one comes to mind, but out of general courtesy I won't name- and will hope for different), especially at the smaller towns and cities. However, if money can be made (or operations will be subsidized enough) another airline will step in.