A History of United States v. Microsoft – Pixel Envy:

In other words, how much is it okay for a first party to advantage themselves over third parties? If there is a line, where should it be, and who should establish it? There is obviously deep resistance to government intervention among the industry and its commentators, but there is also little incentive for operating system vendors to restrain themselves from prioritizing their own products and services. Gates, at this time, could not articulate any reason why Microsoft should not follow any competitive path it chose, even if that meant doing things third-party developers could not.

And that, of course, is exactly where Apple is now. What limits would Apple set themselves? There are none, that I can see.