But this is definitely not the case with USDT. USDT, as we all know, is the most traded coin in the whole cryptocurrency market. USDT's 24-hour volume is even way higher than that of Bitcoin's. Bitcoin's volume is not even half of that of USDT's.
But whatever possibilities are with USDT, they are going to be temporary. Although a USDT crash may shake the whole market, it won't cause the market to crash as well.
Back in the 5-6 months ago, when XRP still on top 5 AFAIK (it's mean XRP has quite amount holders) there's a FUD of SEC lawsuit against XRP. Many big centralized exchanges has announce to delist XRP (some already delisted) it make XRP got dumped from $0.6 to $0.2 or -66,67% but it doesn't to effect other crypto e.g. (BTC, ETH etc) instead of dump, the other crypto continuously pump.