the article doesn't make much sense, they are saying that making their own GPU so they can cut IP licensing out, which of course there will be no way around that I think, they have to get IP from someone......
It's not the first antiquated rumor he's digging up lately; in fact it's the 2nd strike I've seen after the Samsung GPU development horror picture show Eventually he's stuck in some sort of timewarp, it can't be explained any other way that he reproduces that late quite old stuff. Other than that it's an "exclusive" just don't ask me for what exactly.
I promise it won't hurt; click only if you have 5 minutes of your time to waste
I think Apple would be best off sticking with IMG for the foreseeable future. They're probably IMG's largest customer by a high margin and I'm sure IMG will do a lot to maintain that relationship. Including more customization to their needs, which there have been a fair number of signs of already.
Rolling their own GPU could put them in a licensing headache when it comes to maintaining compatibility, for example with PVRTC textures. And it removes them from the patents that IMG has which can better fend off trolls. If they're really serious about it buying IMG is probably the best course of action.