You seem to be forgetting about an exchange. Tether themselves exchanged USDT for USD. As long as they were able to continue honoring redemptions Tether remains pegged to the dollar. If I were to decided to sell 1 USDT for $0.50 right now, that doesn't mean that Tether has depegged. Just looking at the trading prices off of random exchanges doesn't tell the whole story.
Tether's direct redemption process is thoroughly opaque, limited to the big boys, and according to their own TOS only possible when they feel like it. So the price on "random exchanges" is the real price.
Great thing they are 100% transparent about redemptions they have honored! By the way, their terms state they don’t actually need to honor their redemptions with USD.
Here, have some Evergrande debt in exchange for your USDT.
I guess you understand the concept of arbitrage, but you don't know the word. Also, do you just regurgitate information you have previously heard or have you actually tried to exchange DAI for tether? You can't... and there is no auditing mechanism for Tether. They can print as much Tether as they want with no oversight.
