Other companies are focused on specific markets or trying to latch onto making a game for established markets.
Nintendo takes the approach of looking at what would be fun first, then building that idea from the ground up to be both profitable and work best as a game. A simple concept that few companies actually do, as most companies are focused on the end product or the consumer and trying to make a game based on that target. In this way, few games like 'Nintendogs' or 'WiiFit' come from third parties as they are too risky and do not have a preset genre or fanbase before development. Whether its a Bounding Plumber and a Sword Swinging Elf or a handheld Pet Simulator and a Fitness Aid with an $80 attachment, Nintendo has been sticking its neck out and trying to look for new markets and genres to create ever since its entrance into the gaming market.
Plus there's the fact that Nintendo doesn't have as much direct competition as other companies, follows through with advertising, is one of the largest (if not the largest) gaming companies in the world, etc etc.
Six upcoming games you should look into:
