The Android numbers can climb to a clear majority without affecting the iOS ecosystem. Why?
Android customers don't spend anywhere near as much money per person on apps. Many don't buy paid apps at all. Developers usually follow the money, so iOS is where most of the cool new stuff and creative apps will happen first. Customers who want the cool apps will continue to buy enough devices from Apple and apps from the App store to keep iOS with a healthy and profitable market share, even if Android use climbs to 50%+.
Android customers don't spend anywhere near as much money per person on apps. Many don't buy paid apps at all. Developers usually follow the money, so iOS is where most of the cool new stuff and creative apps will happen first. Customers who want the cool apps will continue to buy enough devices from Apple and apps from the App store to keep iOS with a healthy and profitable market share, even if Android use climbs to 50%+.