
WOW:o
i never knew SS was released after POA ans POAU, im shocked
Artbox didn't get the Harry Potter license until the time of POA. Previously, Wizards of the Coast had the rights as part of their package for the trading card game, and they issued a wide-format set for SS that is usually thought to be unimaginative. They certainly didn't promote it, and it's available in bargain bins still. The cards were even distributed like a TCG set, with "common" cards 41-80, "uncommons" 1-40, and "rare" parallel foil versions of 1-40.
After the success of POA and POAU, Artbox knew there would be an opportunity to go back and issue sets for the first two movies. Their first problem was trying to figure out how many Potter sets they could sell in a single year, since they had to plan for GOF and GOFU. They postponed COS a little bit to make room for MM.