Asbestos, lead, CFCs, DDT, there’s a ton of examples of where it worked. The question as usual is where regulation is appropriate and how far it should go. Banning lead pipes was obvious, and it worked once people understood the downsides and limited upside, but banning drugs has been a failure.

You have to look at the demand side of the equation, because creating black markets isn’t a good idea, and neither is creating widespread resistance and discontent. Governments aren’t all powerful (thank goodness), so regulation has to focus on the stuff that’s most harmful and has the highest chance of success.

If they were very profitable instead of just getting by, more of them would appear until they were just getting by again. So that's not a sign of lack of impact of your spending.