[holymadness]

You are right that anything could happen, but that doesn't make it likely.

Apple has an interest in making its ecosystem as attractive as possible, even if that means opening itself up to competing services. Its rivals have an enormous interest in making sure their products and services are available on iOS, so long as Apple continues to create the most successful phones and tablets on the market and its users continue to spend more money than the average consumer.

I don't see either of those reasons changing very soon.