He’s in Canada and I think some industries can still get it for legacy (old) equipment in the US but it’s pricey usually here.
It may be damaging on an individual basis, but large scale is different and not that simple. retrofitting every AC system in the US would be problematic and not environmentally advantageous over a slower roll out of new refrigerant. New equipment, supplies, travel, logistics, costs, manufacturing costs, and ramping up for inordinate one time production, and labor are an environmental disaster too.
134a is nice but asking companies to produce enough to retrofit every US unit in a short period of time requires manufacturing, delivery, storage, etc. and companies would have to ramp up for a huge 1-3 year supply boost and prepare for a HUGE let down when it’s all done. That’s a manufacturing and logistics nightmare.
Slow phase outs and roll outs are economically viable, and imperfect but reasonable environmentally as well.