Amazon is not going to leave before they absolutely have to. Every second they hare on the iPhone increases their exposer, makes them money, and keeps their customers happy.
It is more than that. The latest estimate I've seen says that Amazon has 58% of the ebook market, while Apple has 9%. With every Kindle book bought and every day that passes under the status quo, Amazon's leverage grows. They have no interest in forcing a confrontation even a minute early.
