50 years is a pretty nice longevity all things considered. Vinyl will outlast anything but I thought that the species it derives from went extinct?
I have found personally that the adhesives available to use in combination with the upholstery foams is only good for about 20 years.
There are some surprisingly difficult decisions to make. I don't aim at 50 years now. 20 years is even doubtful as well?
Good quality leathers will last 20 years or more. The stitching done on the original dash covers is close to being impossible now to duplicate. Even the thread quality and composition enters into the picture now as well.
The seamstresses used back then are beyond just plain high quality talent. It is almost "Godlike" if you ask me.
You can find leather workers that can do wallets but those are only a stitch run of a few inches at a time. Nothing like a dash as complex as a Pantera type 1 dash.