'Taxes' are precisely the problem I have with MMT (as it has evolved from an explanatory proposition to a prescriptive proposal). In the U.S., at least, it has been demonstrated since the middle of the 1960's that the Congress, which must raise and lower taxes, cannot act with the deftness, much less the intellectual acumen that managing the economy requires. That is why we ended up relying on the central bank to try to manage the economy.
A permanent 'quantitative easing'--but with built-in protections against inflation--is a better option. It would make the existing economy self-regulating.