Come to think of it, before this whole FTX and Binance drama begins people already have it in mind that USDT will go to zero, some are speculating that USDT will bring the next bear market to crypto, instead it started with FTX and now the banks, other stable coins are the ones affected, no single touch on USDT. This is 
laughable.
This has nothing to do with those companies that you mentioned. When they collapse the stable coins can hardly be affected but even if they don't, the stable coins can still collapse in their own if they experience an issue related to the banks or on how they store their reserves like what happened with USDC last time. laughable. So many people are bitter with Tether and said it will go to zero but Tether just proved them wrong. Other stable coins are already collapsing but Tether remains to be strong and I bet so many people already transferred with it. In case Tether fail, I don't think it will make the whole crypto crash. See what happened to USDC? In fact the market have been pumping that time.