There are some very famous wines that are extremely limited and inspire a cult like following; and then there is Clos Rougeard. The tiny amounts of Cabernet Franc and even tinier amounts of Chenin Blanc that the Foucault brothers make in Saumur-Champigny are among the most rare and sought after bottles in France and now the U.S.
What's the trick? Well it's a bit mysterious but basically they possess very old vines on special terroir. Their yields are tiny, farming is meticulous and the cellar is deep, dank and cold. Those few of us luck enough to visit can attest to layers of mold and caverns of oak barrels with various vintages slowly fermenting or resting for years before bottling.
The wines are stunning. They can age probably forever. And they are extremely limited.