Harry Potter is a massive brand. The books have spawned movies, theme parks, and now a spinoff series of movies. The franchise is not going anywhere, but in the early 2000s, Electronic Arts thought the brand was just a fad that would never last, canceling an MMO they had in the works.
The game was in development between 2000 and 2003, just prior to the release of the sixth book, Harry Potter and the Half-Blood Prince.
Perhaps it was all for the best. EA would probably have ruined it.
[Source: OGL: Original Gamer Life]