Many game studios are being dropped following a bit of an economic downturn in the United States and globally. Activision has to deal with being agile enough to survive the economic times like anyone else and has dropped a few games that had great potential.
Gamers continue to ask the question, "why?" when some of their highest potential games were dropped to the floor. Ghostbusters and Brütal Legend are a couple examples of games with eager fans already salivating prior to its launch. Some of these fans are a bit ticked off that Activision named them as dropped franchise opportunities.
People ask why a company holds one "mediocre" title while getting rid of other potentially awesome ones. Don't forget, this is a business and a good studio/publisher is going to make good business decisions without emotional attachments - those that bring emotions into play may end up with a highly valued product (to them) with no additional potential and lower revenue. This isn't to say developers cannot be passionate about their games and their industry, they just have to build games gamers will buy and continue to fall in love with release after release.
Atari has picked up Ghostbusters: The Video Game, and will be publishing it in 2009.