Additionally, say you hold 50% tether and the rest in a mix of coins. Your portfolio would be cut in half. How does that result in other coins being purchased if people are uncertain of tethers true value and unwilling to trade for it.

Then there’s the whole using tether as margin for leverage or if your margin is based on tether, and that disappears, your position will be liquidated. Now add the layers of derivatives that are quoted and settled in tether. Additionally what exchanges can you trust that will let you cash out in an event like this? People will run to the doors and liquidity will disappear creating a larger sell off as people seek shelter in liquid assets.

There's also drugs and gambling! /s