What on earth are you talking about? A pure points system that isn't deeded? All current
DVC is deeded.
The rules of the BVTC are very clear. There are a lot of changes they could make, like charging a premium for non-home points at Poly2, or just completely removing resorts from BVTC. But fundamentally changing the way the deeded system operates isn't possible with current resorts.
But sure, in theory, they could start DVC2 and just not interact with DVC1 at all, or not have deeds or only sell Sunday-Sunday weeks or whatever, in theory. Future resorts could do whatever they want (except DLT, I think, because it has filed a lot of documents already).
I think there's a decent argument that legacy points were promised future resorts. So, IMO, the theoretical future system would have to take those points, but it wouldn't have to be cheap.