I am sure there is some way, nutrition wise, to keep phylloxera at bay, but history has proven that it tends to take over entire areas. I met a guy in Spain who claimed his Grandfather knew the phylloxera wave was coming so he pulled all his vines ahead of it, put in resistant rootstock, and was the only game in town for a few years when every one else in his region was dealing with sickness or replanting themselves. That said, I think the consideration that own-rooted vines would be better is inflated; nearly every block will have a section with own-rooted vines as the best way to replant a dead vine is to run the neighboring vine’s end down to the ground to get an easy replant. If there were a huge advantage to is people likely would have seen that result by now in practice rather than just in theory.