Yes, but as long as nothing is stopping them from simply minting out of thin air, I wouldn't bet against their ability to keep pushing the prices up.

Daily volumes of tether trades are consistently a high multiple of the total supply. (Today it's 130bln vs 30bln.) So I don't know if it's safe to even trust that number.

As per Steins law, anything that cannot go on forever must eventually stop. Question is how long?