From wikipedia:
The use of resistant American rootstock to guard against phylloxera also brought about a debate that remains unsettled to this day: whether self-rooted vines produce better wine than those that are grafted. Of course, the argument is essentially irrelevant wherever phylloxera exists. Had American rootstock not been available and used, there would be no V. vinifera wine industry in Europe or most places other than Chile, Washington State, and most of Australia. Cyprus was spared the phylloxera plague, and thus its wine stock has not been grafted for phylloxera resistant purposes.
Well, the phylloxera came from the Americas. With the advent of steam powered ships, the aphids managed to survive a trans-Atlantic voyage, instead of dying off, as they had in the much slower sailing vessels.