Well it possible, remember that Tether has been in the hot waters for many years and there have been claims that their USDT is not back 1:1, actually it's 0.074$, and then there is no audit or at least they are not allowing any third party to audit them. So if SEC goes after them and freezes all usdt movement, it will have a drastic effect on crypto ecosystem as a whole. Not that it will collapse but for sure we will see a massive downward spiral and it will be chaos.