This is insurance. Literally insurance.
You pay a monthly fee in return for a good, service or cash payment should something happen.
however in the USA, something odd has happened. For what ever reason, be it legal, cultural or other, copay, crippling buerocracy and down right greed has stopped the health system working properly.
The problem with a "netflix" model, is that doctors can currently prescribe anything, regardless of cost or efficacy. There are legions of people around the USA bribing doctors to prescribe expensive generics. Until that practise is stopped the US system is sunk.
For insurance to work, US doctors must follow national guidelines laid out by a scientific body (ie NICE in the UK) any deviation without justification would/should lead to fines and censure. They would set out a list of drugs that work for certain conditions, anything else is either poor value for money, or the wrong drug.
The very fact that medicare is legally barred from negotiating volume discount tells you that some deeply wrong has happened.