They've released 3 devices this year (iphone SE, 9.7" iPad Pro, 2016 rMB) with a headphone jack. And there is still a decent possibility that they will release MBPs at or around WWDC with a headphone jack (since I assume Apple is waiting for the release of the iPhone 7 to bring about this change in audio interface - or why not do it already). That is going to be really weird. You could easily have someone buy a macbook from this year and buy an iPhone 7 later this year and have to use an adapter or completely different headphones for each device which seems...inelegant.
I think their best course of action is to push wireless headphones ONLY for the iphone 7 and DO NOT come out with a lightening capable set of headphones. Instead invest heavily in a very small adapter for regular 3.5mm headphones so they can be used with the iphone 7's lightening port. Trying to introduce a NEW headphone lightening interface (that is basically Apple only, and introduces a lot of fragmentation for their product line) seems silly. Don't try to reinvent headphones. Just push wireless for the iphone 7 and give people a really good adapter (for regular headphones) if they need it.
Full disclosure: I could care less about headphone jacks in the iphone 7 but I really, really don't want the 3.5mm headphone jack removed from macbooks/ipads. I will probably always be cross platform (I use an android phone, I'm sure many others have an iphone but also use a PC). In that scenario moving to a new audio interface ONLY for apple devices would really suck.