UnitedHealth drops 1 million seniors, the biggest Medicare purge in two decades.

[Soul_of_Wit]

44. Think pre-existing conditions

You can go back to Medicare, but... Medicare (the true, vanilla kind) has no pre-existing conditions. This is true as long as you maintain Medicare coverage. Having Medicare Advantage changes that. If you then go back to Medicare then your premium can be higher, due to any pre-existing conditions. It will be higher for the rest of your life.

Why might you have to go back to Medicare? The obvious reason is that you aren't as healthy as you once were. Folks get older. Your private insurer (remember, it is not Medicare) may refuse to cover something which costs them too much. The reason Advantage plans can offer perks is precisely because they avoid paying for expensive care. The other reason Advantage plans can offer perks is because they cost the federal government more than Medicare does.

EDIT: To clarify, the cost of the pre-existing conditions will be an increased cost for a Medigap policy. These are typically purchased as supplements to vanilla Medicare. They assist with coverage for the 20% co-pay inherent in vanilla Medicare. These increased costs are on top of any late enrollment penalties.