I don't think they expected them to sell as well as they did. The manager where I got mine remarked on how they've already gone through several shipments.
And for the person above that figure that the games have made $8 million, don't forget that you also have to get a value meal - so that adds in about another $5 million or so.
"It seemed to me they probably just bought some sucky games that had already been developed, and slapped the King in there. If so, they might be making quite a bit of money here. does anyone know?"
Well, as has been pointed out many times in this thread, the games are actually good. But anyway, the racing games re-use the same characters, and some of the music has already been used in BK commericals (like the Coq Roq songs) so I'm betting they really didn't have to break the bank to make the games.