Why did it work? Well, as it turns out, there were many workable substitutes: not all as good, initially, but with a little work, they've improved enormously. As with all substitutions, they have other effects, some of which we are now concerned with. They propose practical problems, and, as with all practical problems, they can be solved after some work, the only remaining question being whether it is necessary to solve it now, or adopt it gradually over a period of years.
But one other note: the analogy that supported the original research appears to have been just an analogy, and not a scientific fact. There's a relationship there, but it may be as a contributory cause, rather than as a main one: the ozone hole reached its second-largest size in 2003 (not a reasonable prediction after the ban). Should something have been done? Yes. Does more work need to be done? Yes. Did the panicky people calling themselves "environmentalists" deserve to be ridiculed for the wacky nature of their vision of the future based on their misreading of the original reports and testimony? Yes.
And that's the problem. Global warming. Need to talk to someone who isn't ridiculous about what is necessary other than the centuries long movement away from carbon heavy fuel sources toward hydrogen. I think we need to do more of that: and I see that Shell Oil agrees (as they would, given that they are in a position to act as distributor). It seems to me that we're missing two thoughts about global warming: 1. Is it a problem compared to the current state of affairs? 2. Is it hard to manage if it is? So far, I don't think there has been much effort spent on these two questions.
UPDATE Once again, we are being lied to about the environment by the UN, and the hysterical ninnies that want to shut down all objection to their weirdly stupid politics by pretending that their politics are "scientifically proven". This little omnibus of environmentalist myths will doubtless be cited by someone near you. Smile gently. Step away from sharp objects. Ask a few minor questions: "We are feeding successfully people all over the world, more than at any time in history. Do you think these people are important?" "Have you ever driven from coast to coast in the US? Did you see the uninterrupted urban landscape?" "Are you aware that by almost every ecological measure, things have gotten better, not worse, since Earth Day in the 1970's?" "Do you have any memory of the prior hysterical headlines and stupid reports which pretended to describe problems as more severe than they were?"