Without a much more granular understanding of economic life, MMT will not work. To begin with, there is the malevolent influence of finance-dominated capitalism, "rents > growth" in Piketty's famous equation.

But one thing missing entirely is the fact that there are always two economies at work, the consumer economy and the production economy of goods and services. They operate at different velocities relative to each other. There is a complex interaction of monetary flows that needs to be understood and quanitified.

There seems to be barely an awareness of this fact, which economists like Schumpeter and Kalecki had some inklings. See B. Lonergan, For a New Political Economy, and also his Macroeconomic Dynamics (university of Toronto Press). A basic companion is Philip McShane, Economics for Everyone (Axial Publishing, 2017).