How does this argument not apply to everything? The counterfactual (where 3M continues to produce these) is ... obviously bad? Producing materials that are bad for the environment and human health! Now less is produced, at least in the short term.

An example where your argument doesn't play out like you say: many chemicals manufacturers decided to no longer sell chemicals that would be used for administering the death penalty via lethal injection. So many did this that states _had to basically stop applying the death penalty_, and basically try and trick companies to sell them the materials. A win for those who pushed for that to happen (mitigated by the endless cruelty of the SC but..). Alternative companies didn't show up to "fill the gap".

At one point doing things actually matters. Especially when we look at how large conglomerates own many parts of the value chain, at one point the end result is simply that these chemicals stop being used.