There was no Medicare expansion under the ACA. There WAS a Medicaid expansion, which was the single largest expansion of single payer since the '60s. Medicare is "totally reliant on the private sector", every medical service or treatment paid for by both Medicare and Medicaid is entirely provided by the private sector.

As a long time small business owner (now retired) I have bought medical insurance in the individual market for over two decades. The ACA gave me MUCH better coverage, the best I ever had, for about 1/3 of the pre-ACA market premiums. It allowed me to hire private respite care for my elderly dad in my home, paying a living wage to the woman/friend by providing her with affordable insurance so that the wage I paid her was a living wage.

Governor Romney vetoed "Romneycare" in Mass. several times. The progressive state legislature crafted a bill he would not accept, given its left lean, he vetoed, they overrode. Under Romneycare 96% of Mass. residents have health insurance and 70% of residents are happy with the program. You might consider reposting less propaganda and doing a little research into the subjects that interest you;)