Rather odd to talk about wine continuity across the centuries without mentioning phylloxera: https://en.wikipedia.org/wiki/Great_French_Wine_Blight
So the seeds might be the same, but the roots often aren't.
So the seeds might be the same, but the roots often aren't.
Interestingly enough, a few weeks ago I had a Riesling from Washington that had "100% vinifera rootstock" prominently printed on the label. Not every part of the world got hit by phylloxera. I understand that some parts of South America (either Argentina or Chile, I can't remember) were spared as well.