|Angry Birds plush toys at an open-air market in Seoul, South Korea.|
I don't think these were authorized, but I wasn't able to ask.
More than that, when the console maker throws in new features like 3D or various sensors or motion control, or even added buttons, it all takes time for developers. They have to spend time experimenting with the new features, learning how they work, and hopefully coming up with useful and fun ways to use the features in a game.
How high are we talking about? Game budgets for the 3DS and the NGP are expected to be over $1 million dollars. That's your price of entry... so you can see why a small developer used to iPhone games might balk at the idea. As a contrast, Angry Birds cost $140,000 to develop, and that was considered a very high budget for a smartphone game. Many smartphone games from small developers are costing thousands of dollars to develop, and even then many don't make back their investment. Which is why independent developers need to tread carefully when deciding on budgets for their games.
And clearly, if you are thinking about bringing your smartphone game to the 3DS or the NGP, you'd better have a lot of resources handy... And a great deal of confidence in how many copies you can sell.