Niche games eventually (hope) to become a not niche game. I can't think of any artist in any field that doesn't ultimately want everyone possible to love what they're putting out. The problem is that some niches will grow, and some will remain niche.

Just look at Half Life. That had all the hallmarks of niche at the time of release in 1998. A new developer created an FPS that went against every convention. For the first hour of the game, there was no gunplay, conflict, or anything, really. You were just a scientist going to work. But that did strike a chord, word of mouth grew, and Half Life is one of gaming's juggernaut franchises.

Gran Turismo was created to be a hard core sim of racing in the days of Ridge Racer. It ended up being one of the Playstations top titles.

The list goes on. Counter Strike, Final Fantasy 7, and World of Warcraft (I mean, how many people were playing MMOs before WoW in the grand scheme of things?).