These policies are evolved by insurance carriers typically as wrap around the Original Medicare insurance and contracted with Centers for Medicare and Medicaid Services on annual basis. Insurance carriers generally add additional benefits over and above Original Medicare to make the policy wholesome and easy for you, and ideally include Prescription Drugs coverage making it a one-stop shop. Insurance carriers sell and service these policies under control and standards set by Centers for Medicare and Medicaid Services. 

The insurance carriers have the power and advantage of creating networks of service areas of different plans, providers, hospitals, pharmacies, and integration with similar out-of-area networks in 50 states. 

The coordinated healthcare by networks of providers generates higher volume of business and drives down healthcare cost for you. Not everyone can be happy, but the goals and objectives are noble. When you want to sign up for a Medicare Advantage plan with Prescription Drugs Plan, you must be enrolled in Part A, Part B and Part D with the Medicare.