IMO they've been doing this since the iPhone launched; their MO seems to be ~take what people hack into the software through Jailbreaks + what the competition is doing + apps we like, refine / distill that, and make it part of iOS.

And I would say that for most people, this strategy has been very successful, even though e.g. jailbreakers might get a more advanced version of something that eventually gets integrated many months in advance. It's basically free R&D and proving out concepts for Apple.

I wonder sometimes if they actually know about other channels for jailbreaks, but don't close them all at once due to the value this provides. Of course, they could never admit to this / have a paper trail for it, software is hard / complex, and jailbreakers are amazingly talented, so maybe I'm crazy, but that's what I would do in their position.