When EPA did its thing in 1994. I predicted a steep rise, then gradual decline in the cost of R-12. Figuring that a replacement would come out, and the demand would fall. The price went up for a while. And the replacement blends started to come out. I used R409a for quite a while. And now using FX-16, I think it is, works about the same and a bit cheaper.
Now, there is a lot less equipment which uses R-12. I still see the equipment, now and again. My own refrigerator is R-12. And, I service R-12 equipment on a regular basis.
Same thing I'm expecting with R-22. As the gentleman comments, in another thread, he got his car for R-12, and now doesn't have any cars which take R-12. I can easily imagine that in the next decade with R-22 equipment. I'll be hanging onto the old stuff as long as I can, my trailer is cooled by two window shakers using R-22. My church has plenty of the old equipment in use.