One year and—barely—nine months. That's what it has taken Apple to invade 19 percent of the total US portable game market, while the PSP sunk from 20% to 11%, and the Nintendo dropped 5%. And that's only revenue.
Taking into consideration that games in the App Store are cheaper than in the PSP and Nintendo, and that 30,000 titles have been released since its July 2008 launch, I wonder if the actual unit sales figures are quite larger.
In the general gaming category, Apple has taken over 5% of the market, while the rest of the portables have increased to 24% from 20% and the home console market has dropped to 71% from 79%. Knowing about these sharp increases—and knowing that iPhone games are still in their infancy—it's not surprise that game developer are choosing the iPhone en masse.