I dont think you have to be worry at this point...maybe you are right in some points but you must not forget that tether is already on of the strongst coin in the crypto market and even if somthing bad will happen to usdt will not happen suddenly
Do you understand the concept of a market crash? Why wouldn't it suddenly crash and even if it slowly went down at what pijbt would you sell? 90 cents, 80, 50 (having lost hope it'll rebound).
Worryingly, this means that at least some of the cryptocurrency users are holding their wealth in Tether, rather than using it solely for trading. It is just like holding your coins in exchange wallets.
On its own, it doesn't.
The volume reported on cmc is 5x the available usdt. Assuming this ignores futures on exchanges then there might jot be many holders of usdt and some holders might be companies like binance also where users have set stop losses/buys (in both directions).