Ask HN: How often do gold-rush opportunities like iPhone’s App Store happen?

What are the requirements for this to happen? For example, the internet created a whole new ecosystem of opportunity, but a bunch of government funding went into developing it. A bunch of work went into developing the iPhone. So is a new platform a requirement? Does anyone have any predictions for what future platforms might come into existence, and what signals are you basing these predictions on? Is there any pattern in the frequency of these kinds of game-changing platforms?