Which is a bit like MAME for digital cameras if you think about it.
Several curves are intersecting bizarrely here. The approaches and skillsets and game types that were prevalent 20 years ago are still valid, like bacteria. They just keep migrating to new low-powered platforms: in-browser Java, Game Boy, mobile phones. At the same time, all platform niches (mobile phone, PDA, console, desktop PC, fridges, etc.) keep becoming more powerful. And this allows emulators for old platforms to become viable.
So, about 5 years until we have XBox games running on our wristwatches?