Exactly. It's like assuming everyone has a Mercedes, a smartphone, or a butler. M4A is also not a solution for universal healthcare because Medicare isn't very good: it requires multiple types of paid co-insurance, rations healthcare, and doesn't pay doctors enough to motivate them to help patients. Medicare is a bare-bones, half-measure that doesn't offer a healthcare system. The common refrain of "It's better than nothing" is an invalid rationalization to settle for substandard healthcare.