That is apparently what’s going on. Apple’s iOS 7, to be used on the iPhone, iPad, and iPod Touch, has been in development for the longest while, but is still coming up late, so as a result Apple is pulling engineers off of the Mac OS X team, and into the iOS 7 dev team to speed up the process. The resulting success would be so that iOS 7 would debut during or after the World Wide Developers Conference (usually where new Apple devices are announced).
As Apple/technology information veteran, John Gruber explains:
“What I’ve heard: iOS 7 is running behind, and engineers have been pulled from OS X 10.9 to work on it.”
The fact is, we are all willing to wait if it means iOS will finally have some new design tricks up its sleeve.
Via: Daring Fireball