Soldato
That is quite an assumption.
Not saying it is correct or not, but we have no idea of what the Nvidia hardware in their cards is capable of, Adaptive Sync compatibility might very well be incorporated into Nvidia cards, especially seeing as this technology started out as a laptop power saving feature.
Now whether Nvidia will add functionality to their drivers is another matter, as surely this would harm their Gsync product.
DisplayPort 1.2a specification is an Adaptive Vsync requirement, Nvidia need to deploy 1.2a onto their gpu's before they can run Adaptive Vsync.