Actually a good example, you should look at the actual losses incurred by investors in Madoff's fund. It would probably be educational if you think tether could "go to zero".
Here's Terra Luna price today: https://www.coinbase.com/price/terra-luna. Clearly, it is above zero (it's $0.000170 for those curious.) I think I would be happy to concede one USDT is worth definitely above $0.000170 while also maintaining it's worth definitely below $1.
Another important lesson is to look at Luna and understand the difference between it and tether. Luna was highly leveraged and had essentially no collateral with exogenous value. Tether is sketchy and potentially fraudulently under collateralized, but clearly has substantial USD collateral.
Terra was an algorithmic stablecoin (ie not really a stablecoin). It can't be compared to Tether.
There were fundamental flaws with how Terra worked. A reductive way to describe it is, Terra was backed by Luna. Luna's price was determined by the market. Luna's supply was infinite. The price would go down if market demand didn't keep up with supply increases. Doomed from the beginning.
