Gamers always want new stuff. We're the sort of people who are never really satisfied with what's currently available and always looking forward to what's coming up. It's no surprise then that the masses are always clamoring for new IP's to be developed into video games. New properties seem fresh and exciting but are also fraught with risk for the developer's and publishers.
In fact, despite the supposed leanings of the audience, a lot of new video game properties fail. For such a forward-thinking group, we are sometimes reluctant to try new things unless they hit a very specific and ever-moving sweet spot. You never really know what's going to take off with the fans, and sometimes even the much acclaimed new titles fail to be a commercial success. Everyone seems to prefer staying in their comfort zone.