Actually, anybody (who owns an iPad) can sue.
Doesn't mean the suit will go anywhere, though.
On antitrust grounds it won't go far, though:
- Apple's 19% share of the smartphone market is hardly the stuff of monopolies.
- On the tablet side it is much too early to crown anybody, much less Apple. Their 60% market share is only going down as competitors get ther act together and the buying public gets a feel for what pads and tablets can and (especially) can't do.
Restraint of trade? Yes, that could fly and not depend on market share.
But it would have to be Amazon or B&N that sues and they actually benefit from the policy, or Kobo or the smaller ebookstores that are actually damaged by the Apple policy. However, the fact that Apple "merely" changed the interpretation of the rules makes success there far from likely.
Actual owners of iOS devices are the biggest losers and could sue for loss of functionality/value, in a class action suit (preferably in east texas) but that nobody has done so tells you Apple owners are not that upset. The Apple kool-aid is mighty powerful stuff.
That leaves governmental action and setting aside the number of politicians that Apple may or not have bought, governmental action is slow and by the time they act the small independent ebookstores most impacted will be dead and gone and the big guys will be using HTML5 applets and Apple will be looking at ways to block that off, probably through Safari blacklisting, because no matter what they try, iBooks is not going to get far in this business anytime soon. A turkey is a turkey even if you paint its feathers and call it a peacock.
The ebook business as of now is past the point where any single player, be it publisher, retailer or intermediator can control it; the barriers to entry are low, the number of significant players high, and the overall market fragmented at every level of the supply chain.
The only player that had even a prayer at a monopoly was Adobe, with their well-timed hijacking of ePub, trying to turn ADEPT DRM into an industry chokehold and it failed. Just as Apple has failed, first by convincing the Price Fix Six to adopt their "Agency Pricing" scheme, now by trying to restrict competitor access to their customers.
ebooks aren't like music or video where a handful of distributors control the majority of the content; even the Price Fix Six combined don't get to half of the market supply and that aggregate share is dropping by the minute.
In ebooks the market power resides with the consumers, as an aggregate, not the intermediaries or even the creators. Which means nobody is in real control. Everybody now has to sing for their supper.
The djinn is out of the bottle and getting it back in is not going to happen any tme soon, if ever.