I'm guessing that might be a problem.
You see it would probably be really hard to see if the game is really being sold or is sold second hand (especially on non-english sites), or if the game was sold, but the store doesn't have it any more, and thre's just an old add saying sold out (could also be in various languages).
Example:
Mantis is a game store where I started buying my first PC games way back. Now can you tell me how a program could figure out which games are really sold and which are just second hand copies.
Also the updating of the OWL is quite a problem. At the moment there are many games missing in it and updaters have to keep the list going, since there is no one here anymore who'd take care of the list exclusively. Tom and Timpsi started the list and both of them have been inactive for quite some time now. If there were some enthusiasts to take care of the lists that might help...