"supply and demand" isn't a magic phrase that makes me responsible for what other people do.

Personal responsibility has been an excellent tool for large corporations who make deliberate business decisions causing their manufacturing process to be worse for workers and the environment. Belief in personal responsibility as a serious value is what allowed a scam like recycling to be knowingly pushed by polluters for decades as a consumer-driven solution that requires little to no work from producers even though most products can't be recycled anyway and recycling is, in fact, not a solution to anything in and of itself.