Nintendo already has the upper hand in the video game console market. Its Wii outsells the Microsoft (NASDAQ: MSFT) Xbox 360 and Sony (NYSE: SNE) PS3. But with its market penetration so high, the hyper-growth has to start slowing.

According to The Wall Street Journal, "After overseeing several years of rapid growth at Nintendo Co., President Satoru Iwata faces new challenges: how to keep players of the company's videogames interested, and how to cultivate a new wave of customers."

Nintendo's problems may be beyond its ability to solve. It can bring out new consoles and games for its current products, but the industry as a whole may be facing a slow period.

The newest game platforms are now a couple of years old. That means most of the ready buyers probably own one. Going after the market of people only modestly interest in the products will be harder, especially when compounded by a weak economy.

It may be easy to focus on Nintendo because it has such a large market share, but the entire industry may have problems until the next generation of consoles brings a large number of buyers into the market again.

Douglas A. McIntyre is an editor at 247wallst.com.