The United States has changed its mind about refrigeration and is now following Europe's lead. The new refrigerant is R600A, which doesn't have a big effect on the ozone or global warming.
When I say "isobutane," it may sound scary, but there is less than a big lighter put into a fridge's sealed system (45g). Except for built-in fridges, which won't have to be R600A until 2025, all new fridges have to be R600A as of January 1.
R134a is no longer being made, so vendors can only sell what is already in stock or what has been recovered and reclaimed by only two entities. If you break the law, you could pay a fine of $44,000+/day, go to jail, or lose your license.
Countries in Europe have been doing this for a long time. It is also against the law to put a flame near gas containers that aren't sealed. This means no more brazing, no more fire alarms going off, and no more burning things. Only Lokring technology is used, and yes, I did spell it right. So, if technicians want to stay in business, they should get on board, and if manufacturers want technicians to fix their products, they should make sure that all the fittings are easy to find.