It was NOT only sold during the holiday rush of '05. It was released in summer 2005 (possibly a bit earlier, I can't recall exactly) most likely with the intention of boosting sales in what is traditionally a slow season for the game industry. There were no competing console price drops that year, so that couldn't have been the deciding factor. I don't recall it being an exclusive, but it may have been. It is quite rare though (again, slow season = low volume and low sales).
On a side note, LULZ @ this listing.
http://www.amazon.com/gp/offer-listi...condition=used
No case or instructions, fail. The games weren't specially labeled, just repackaged normal, retail copies. Any asshat could just list both games in this manner. Hopefully nobody will fall for that load of crap.