I'm so glad you have started interviewing these folks that most people wouldn't have ever thought to reach out to. There are a lot of interesting nuggets that people can get about the history of the franchise from people with relatively boring-sounding titles such as "marketing director."
One thing that struck me was that Hasbro/WotC was making more cards in order to meet that initial demand. One of the reasons given when TPCUSA sued them in 2003 was that they were overproducing cards to kill the market. It turns out that they were doing that for a while though, and Hasbro even lost a lot of money in 2000 because the demand didn't keep up:
Alan G. Hassenfeld, chairman and chief executive, said the company's Pokemon cards were "still selling well." But, he added, "we were too aggressive in our forecast following incredible demand in 1999 and 2000."
Because of a high level of inventory of the company's Wizards of the Coast trading cards, the company said it would write off $75 million in inventory -- hurting results in the fourth quarter.
- Wall Street Journal, December 2001.