* CFCs are used in relatively few products. Greenhouse gasses are integral to how we get food, build, make gadgets, move around, and keep the lights on.
* There is considerable cheating on CFCs in China (source: widely reported)
CFC concentration in the atmosphere has only gone down since the Montreal treaty so it's still a success so far. (edit: I should have said "since 2000", the treaty was a phase-out to zero emissions by 1996)
What happened was that the rate of decline of CFC concentration slowed down[1] after 2012. This was an indication that there were new emitters. China then found the emitters and shut them down. [2]
> The findings suggest that China, which was thought to be the source of most of the rogue emissions of the chemical, CFC-11, has made strides in clamping down on illegal production of the gas. CFC-11 is used to make insulating foams.