The math isn't that complicated. If the programs advocated to achieve those lofty goals require financing that exceeds the available resources then any activation of those programs are insured of failing.
I figured it was something like a resource calculation, which is disappointing because it's totally false, and a perfect example of the point AOC was trying to convey. Here is why.
The resources to provide basic health care, housing, food, clothing, and education to everyone in America (or, indeed, the entire world) are already available many times over. What prevents these resources from being transferred to people on the basis of who needs them is a system that prioritizes transferring them to those with the most money, and doesn't bat an eye at wasting obscene quantities in the name of accumulating more wealth.
Separating the goal of universal health care (which is indeed lofty) from the reality of its implementation, then, is not a matter of mathematics at all, because the numerator is many orders of magnitude higher than the denominator in all senses, and has been since the industrial revolution.
It comes down to how we choose to produce and distribute the fundamental necessities of human life, and who we deem as worthy recipients of the surplus we are easily capable of producing, all of which can be neatly encapsulated by the word 'morality'.