"Most of what Facebook does today, he [Zuck] said, is "building on top of other people’s platforms."
Push comes to shove, I guess Facebook could launch their own mobile platform too? They already have their own Android phone - it's buried inside the Quest headset. But they probably don't need to, unless Apple/Google disallows the use of Facebook SDK by all the other apps in their app stores. Until then, the sweet sweet surveillance data will keep flowing.