Walmart, Walgreens, and CVS? You mean those small pharmacies--two of which also contain insurance companies, and the other one still has its own clinics?

Pharmacies can only give out what people are prescribed, the only things they can push are OTC products. They can't get and sell scheduled drugs without being explicitly tracked.

But you're right about health care in the US. We need a single-payer system to get prices lower, but that means fairness and cutting out unnecessary costs. The whole health insurance industry would cease to exist, and all the people abusing it don't want that to happen.