Because unlike the cost of mitigating climate change (or covid for that matter) the global cost of switching to other chemicals was very small, on the order of single digit billions of dollars. It turns out most people don’t want to radically upend their lives for the benefit of others who knew?

That was a decade ago when there was no real way for the loony opposition to come together.

Because it was a very small problem compared to this one. On the order of a broken leg versus having to cure cancer.

Good marketing likely helped.

A hole in the ozone layer? We had better patch it at once!

Global warming? I never liked winter much anyway.

The conspiratorial explanation is that freon was cheap to make & not patented, while new more atmosphere friendly replacements were patented. The new refrigerants were also fairly drop-in.