the only long term sustainable economy is one that has a sound money where natural supply/demand laws govern it, not a central and politically motivated agenda where money can just poof be made from nowhere, people are falible and complex systems are impossible to control. Ultimately mmt is like relying on weathermen to be 100% on point. Mmt is just a boom bust cycle where debt is kicked down the road and the bubbles grow larger with a false sense of security.