Tether will never reach $0, because if the price of Tether reaches $0, then it's means Tether is not safe anymore (scam), because Tether is a stable coin and is in the top 5 on coinmarketcap, so the price of Tether will always be stable and will not crash to $0, because Tether has a lot of support (high volume and market cap).
Tether will never fall like other altcoins and not fluctuate with the price on the market, tether will remain $1 and will never fall even though there have been panics before because traders did not validate the fake news issue so it fell below $1 but only temporarily, hopefully traders are wiser and do not repeat the same incident in the future.
I know that people are still thinking that a centralized coin can have huge success but believe me this is not the case, exchanges are being pressured by governments all over the place and they are experimenting the pressure we knew it was coming once bitcoin became more popular, the only thing that is needed for those coins to go to zero is for governments to ban them and suddenly those coins will hold no value anymore as governments can easily confiscate them, which is the main reason why bitcoin is decentralized.