[ventana]

These same comments were made a few years ago when the switch from 15" Fuchs took place. Yes, there are fewer choices when trying to replace 15" tires on a Porsche than there are 16" tires but 15" tires are still available. My prediction is that you will see the major manufactures dropping some sizes but the smaller manufacturers will continue to offer them because that's where their market is.
I would caution you against trying to stockpile 16" tires against any future shortage. You cannot stop the rubber in the tires from breaking down and deteriorating. You might slow that deterioration some with oxygen-free storage but at what price? Do a careful web search and I think you will find an above average supply of 16" tires that will work for Porsche applications.

Ventana