While discount programs focus on the uninsured, this is the first time I’m seeing the discount being framed in such a way that it effectively incentivizes paying out of pocket. It’s an important incentive if your goal is to decouple routine drugs from the third-party-payer model of insurance.
Health insurance in the US is actually 3 different services bundled into one: (1) risk sharing for catastrophic care, (2) access to low prices (called "fee schedules"), and (3) tax advantaged pre-payment for non-catastrophic care. 40-80% discount on drug prices essentially competes with insurance company fee schedules, i.e. service (2). By offering what amounts to insurance rates without charging insurance premiums, Amazon is essentially decoupling the fee schedules from risk sharing. That's a really underrated side effect of this product offering, and can have long run impacts on the industry (IMO for the better).