I'm pretty sure a USDT collapse would be a huge blow to the crypto market. Prices will decline for a prolonged period of time.
It will. We can take the example during the time when there was a continuous printing of Tether. IIRC, that was around 2016-2017 and that certainly created an impact as those were the years like we're in a bull run. The thing here is that those printed USDTs were used to buy and stack more of Bitcoin for Bitfinex.No one can predict the future, so lets hope for the best. Just my opinion 
Yep, it's always unstable, volatile and risky but we've been used to that scene and hoping that we get another unexpected and greater bull run without any failure from any of these big cryptos.