Ozone was much easier / cheaper to fix, we could keep doing what we are doing and just change it around a bit. Which is mostly what we did - there was a resurge

Ozone was much easier / cheaper to fix, we could keep doing what we are doing and just change it around a bit. Which is mostly what we did - there was a resurgence in freons emissions, vaguely traced to China. The ugly truth of CO2 emissions is we would have basically needed to massively cut our energy consumption - either by going to renewables more aggressively, at a higher cost, or by outright cutting fossil fuels. We couldn't make small adjustments and keep going as we were. So we didn't.