Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
At least in the US, you can re-implement someone else's functionality and their API but what you can't do is directly take it or leverage it. To avoid it being implied that it is copied, companies generally go to great lengths to have "clean room design" implementations with isolated teams reverse engineering a product and generating the spec. That said unless you ship an entire operating system to the phone, including device drivers and similar, it is unlikely any given iOS app is not going to require the use of Apple's IP. Of course the next hurdle is the possibility of patent infringement which also further protects some of the implementations, even if they are cleanly reverse engineered.

What I do wish is that companies were forced to open their boot loaders/signing keys and provide support documentation to enable others to support their hardware once they stop providing software update support for it. It is not useful having insecure legacy devices in the world that a manufacturer refuses to fix but also refuses to unlock for others to fix.
So its not only possible in the usa its generaly the same.

Especially When there is no ‘fair use’ doctrine in EU copyright law comparable to that of the United States. Instead, EU law provides an explicit list of exceptions from copyrights granted to the rights holders, each with a specific scope.

The Computer Programs Directive stipulates a mandatory exception in article 5(1)

that acts of permanent or temporary reproduction and acts of translation, adaption and other alteration of a computer program shall not require authorisation by the rights holder ‘where they are necessary for the use of the computer program by the lawful acquirer in accordance with its intended purpose, including for error correction’.
What’s going to be interesting to see is if you blow a massive revenue gap in Apple’s earnings, what is going to get more expensive to make up for it? We the consumers always end up paying for these things and it’ll be interesting to see where Apple shift this revenue to. I suspect it’ll end up costing us more money as there’ll be more middlemen in the market extracting value.
Well that would be very interesting considering Apple claims that the store isn’t profitable.

I hope that they actually start improving the AppStore instead of adding a few hundred bucks on the new iPhone
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.