Because they wanted something to be done quickly and easy. I also don't think they wanted to have another studio only resort. VGF was small and so adding these rooms to it kept it manageable. While they discuss the new studios, they sell the entire resort and the ability to book all room sizes.
We have still not seen how well the sales are going with new buyers yet, so we really don't know how its stacking up against RIV.. Again, if they want to keep the long term game of resale restrictions...then this will make sense to make it new and I don't think it will have any problem selling.
I just think it made sense to add the renovated hotel building to VGF...which did have studio issues for booking...so now that resort can meet the demand the current building could not. Plus, the buildings were pretty close to each other.
Poly tower is going to be on the entire different side of the resort than PVB, so it lends itself well to being a new condo association. It makes sense to me that this will happen and as I have said, the title and every thing I have read mention coming to the Poly Village Resort, not Poly Villas and Bungalows...that alone leads me to believe they may make it new...or at the very least, don't want anyone to know which way it will go.