Yes people adapt, even to their livelihood being destroyed. But that doesn't make destroying their livelihood just for your dogmatism a good thing. But we really weren't talking about that; we were talking about the choice between things going on as usual or things going topsy turvy overnight as a basis for your future plans.
As for the fisherman finding new markets; you don't eat the fish they catch, all other markets have the same tariffs on fish as we have. Because WTO.