Same here, I don't have MC on any of my planets and don't intend to. So far, things are going just fine and I have several planets > 100 society now. One reason it works is because I am also not using 20% tax rate everywhere. In fact, most of my tax rates are below 10%. Money just isn't the scarce resource anywhere so far.
I run the default 7% tax without much issues. I just tested my main planet and even without regional government and with almost every upgrade built (no MC Drilling or trading subsidies) and 5% tax I manage to make 70k profit.
