I fully understand the OP concerns. Unless you are independently wealthy, you have doubts plus there are all the horror stories of being denied coverage when you thought you had it.
I recently was "retired" from a large corporation (along with about 3000 other people) when the company was bought by foreigners. That saved my pension (they had to add 5 years to my age and 30 years of service) but because I technically didn't retire, I didn't qualify for retiree health insurance. (I know there are no guarantees they will keep supplying it but it would have made me feel better.)
I don't know how many nights I have laid awake at night worried about health insurance and we don't even have what I would consider a pre-existing condition (we are still on COBRA so we have priced it but not applied yet).
My husband and I have budgeted the amount we think we will need for the 10 year gap before medicare but with the way health care prices have gone up, who knows
As he says there goes the boat he wanted!