https://www.youtube.com/watch?v=LXUBN8SJASw
I guess candidate Trump wasn't aware at the time that we already long had a system, going way back to long before the ACA, where people didn't die in the streets.
Access to health care, primarily through Medicaid, has been around for poor people for generations.
It's already somewhat like Medicare for people who aren't eligible for Medicare - but it isn't for everyone - a person has to be pretty much penniless to qualify.
As I've said before, that has long been the gap in US Healthcare - people who weren't broke who had pre-existing conditions couldn't get insurance until they went broke.
The ACA kind of fixed that - but it also "fixed" a whole lot of shit that didn't need fixing.
Also, Medicare and single payer aren't exactly the same thing - Medicare Part A which deals with doctor visits covers 80%; the patient has to a) cover the rest out of pocket or b) have supplementary insurance or c) can't pay and doesn't have supplementary insurance, in which case the provider eats the difference- which happens, the providers know this, and make market adjustments for it.
Medicare Part B deals with hospitalizations; it isn't full single payer, and Medicare Part D deals with prescriptions, and it also isn't fully single payer either.
EDIT: Oh, and also Medicare isn't fully funded through general funding, it's partially funded through FICA pay role taxes and it's administered through the SSA.