May I just point out that the exact name of this game is Guilty Gear
XX Accent Core Plus
I would think that the high price plus the fact that this edition has not been advertised on sites like Kotaku result in few orders being placed. I am sure that if Kotaku featured it on their main page, it would be sold out by the end of the day!
I also believe that the majority of these have most likely been ordered by visitors to CE.O which is probably where they found out about it