I see a day when all other cars that originally had R12 will be in the wrecker's yard and only street rods, classic/ antiques and Mercedes will be around to use the stockpile of R12. Supply (larger than you might imagine) and demand (only us)will then keep the price down.
The Golden Rule
1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)