People are willing to pay for Heroin because it scratches a chemical itch in our brains. People don't say they want heroin because they intellectually know it ruins their lives and does nothing positive for them.
There's a disconnect between what people want, what they want to want, and what they say they want. This seems to be universal to humans; the connection with capitalism is tenuous, at best.
Such is the predatory nature of the capitalist.