I’m not completely convinced by MMT. I feel they’re onto something, but I’m not sure the world is completely the way they say; it’s like they’ve identified a strong tendency and defined it as the whole enchilada.
But even if they’re completely correct, MMT in itself can’t solve much. It kind of tells you how money works, but it has nothing to say about growth, consumption, wages, trade, inequality, technological change, investment, public goods, externalities, information, unemployment . . . on and on. Some of these same criticisms can be levelled against today’s dominant economic models, but the point is we need something BETTER, which includes not just more accurate but also less limited. The problem is not purely “economic”, it’s a problem of political economy. MMT doesn’t have any politics.