Not sure about that- appears to be down to a single source (TI)- ST, Fairchild and Philips seem to have all obsoleted it, (and NS is part of TI now, of course). I'm sure onesey-twosey will be available for as long as I care about though (at a price).
LM78x05, LM317 are good for the forseeable future.
Best regards, Spehro Pefhany