A private company is making the games. Not a big name company. Why do you worry about the N64 so damn much? It's obsolete.
And of course XBOX, PS2, PS3 and XBOX 360 games are still being made. Wanna know why? There's a demand for them. People still play games on those systems. Maybe if you write to the company making the Dreamcast games they will make some games for your precious N64, otherwise you're SOL.
