"Literally type in 7900XT in newegg search" - I obviously did that and nothing was available yesterday, when I did it. Maybe you got lucky. Maybe now more are available, or if you repeat the search, you come out empty-handed as I did.
As I side note, I should hate Asus for a bazillion reasons - had an extremely bad X1950 Pro from them (custom cooling solution was a disaster, card had to be severely underclocked to play some games without having the VRM hit 120 Celsius), a bunch of DVD writers simply unable to burn dual-layer DVDs, a laptop that was overheating like hell and, although it was used for office work, it died after less than 6000 hours of use, and so on. The Xonars, on the other hand, are pretty good. In the end, any brand has good and bad products, can't be top-notch all the time.
P.S. Agree with you. If I had about 1000 USD and looking for a video card now, I'd wait for the 7900 XTX to become available. In the meantime, I would game the hell out of my smartphones and tablets. :P