I cannot speak to your question about what AARP thinks about the federal program of Medicare but you have some very INCORRECT views on the Medicare program.
Medicare Advantage plans are a part of the program of Medicare - they are Medicare Part C and the plans are under the oversite of the Center for Medicare and Medicaid Services which is part of the government - directly under the HHS.gov office and Secretary.
Medicare Advantage plans are the "managed care" part of Medicare. A beneficiary chooses one of two methods to get their benefits. Traditional Medicare which has NO limit to their out of pocket cost or Medicare Advantage which works with networks of providers in a given area to give beneficiaries a cost cap on their benefits by using co-pays, co-insurance, preapprovals, step therapies and other cost savings methods to control cost to the beneficiary that cannot afford the NO cap cost of traditional Medicare or a supplemental policy that protects against financial ruin from traditional Medicare care.
I too had a friend that was almost financially ruined because of cancer - but they had Traditional Medicare - with NO Medigap policy. Their out of pocket cost soared because of the 20% or excess charges that was up to them to pay.
Traditional Medicare AND Medicare Advantage plan cover the SAME things but in a different way. Neither program will cover treatments or medications that have not been approved as a workable scientific based best practices solution to a disease. A person who has elected for a clinical trial has their cost covered by the trial + regular incidental care thru the Medicare plan type they have chosen.
Medicare Advantage plans are paid by CMS on a factor that is equal to what they pay for beneficiaries in the Traditional program. Plus they get a bonus for their star ratings by CMS on doing a good job + they get a risk adjustment for caring for those beneficiaries that are sicker than the norm.
Medicare Advantage plans can offer extra benefits if financially feasible for them for things like dental, vision and hearing and these things are of real importance to many beneficiaries in their overall health. They may offer other extra care to their beneficiaries like "real" annual physical exams which Medicare does not offer. They may include things like an exercise program that also is valuable to many beneficiaries. AND many, probably most, offer an included Medicare Part D or Medicare Prescription Drug plan to which those in the Traditional program have an extra premium.
Medicare Part C plans can be changed once a year during the Annual Enrollment Period so a beneficiary can pick the plan that best suits their needs. They also have developed Special Needs plans for those with both Medicare and Medicaid and have a chronic disease or live in an institution - this greatly benefits them in care and convenience. They may offer things like transportation to and from appointments, meal delivery when they are convalescing.
The choice of Traditional Medicare or a Part C plan is for the beneficiary to make - based on their health needs as well as their pocketbook. From years of working and being covered under various employee group coverage many, maybe most beneficiaries, are familiar with the managed care structure and prefer it to having to pay for a Medigap plan (a Trad. Medicare financial protection plan) which increases year after year with hundreds of dollars in premium cost.
As a health provider, it is your choice as to which, if any, plan(s) you wish to participate.
The only way we might lose "federal" (Traditional) Medicare is if the Medicare Part A - Hospital Insurance Trust Fund, funded by payroll taxes is allowed to go insolvent - then the program will be cut back to cover the shortfall. Part B is funded by premiums from the beneficiaries (25%) and the General Fund (income taxes) (75%) to cover the usage of the program - those premiums will just continue to rise.
I believe that before any conversation can take place, we should all understand the workings of the program - not by heresay but by facts.
Of course, some MA plans are better than others - some are better for some people than others, and not everybody has access to them. If the number of providers are very low in a particular area - then both MA plans and Trad. Medicare will have problems.
As an answer to this, Trad. Medicare is branching out with other innovative demonstration projects like Accountable Care Organization which are Trad. Medicare plans which help to get an ample supply of providers of different types to work with these beneficiaries.
UNFETTERED HEALTHCARE COST can financially break a beneficiary or a nation.