It depends. If VR is going to stay as a gaming only device Apple probably won't be too interested. If Facebook can figure out what else to do with it I could see Apple building in more support for VR. They would probably focus on mobile first though. I am sure the next Mac Pro will have more graphics power than an Nvidia GTX 970, the current one already does and the top end iMac GPU is close.
Apple devices not being gaming machines has not hurt their sales too much thus far. Its not clear how VR is going to shake out at the moment. Regardless, if you want to play VR you are going to need a $2k gaming pc instead of a $1k gaming pc. Not to mention the added cost of the headset. It may be a tough sell for awhile until there is some very compelling content. Accessibility and cost are both very important in mass market gaming, and so far VR has neither.