I was wondering the exact same thing... Well it is very possible that the bulk of games come from arcades that are not supposed to be selling the carts. I use to buy carts from Alladins Castle in my local mall. Their deal, get this... $25 a cart regardless of what it was. I got KOF 98 there a few months after it was released for $25.... Anyway, new managment came into that store and they told me to go away when I came looking for carts the next time. They said that all carts were now sent back to the main office and sold. Well, maybe some people on recieving found out that some of these carts might be valuable... and sold them to local arcade dealers in the area instead of sending where they needed to go. I don't think that the carts are being stolen by arcade thieves, but it is very possible that internal parties at the arcades are selling the games and trying to keep them a secret. As for the note on the games being reborn, it is a good thought, but the serials are cut out of the labels.. which would mean that a new label would be printed for the game and that could exclude the serial in the first place (like a few I have). Well, maybe one day we will all have to return our carts to the arcades they were stolen from hehe, who knows...
-Nick