You have to predict what those well-capitalized parties will do during a market panic. Decision making seems to change quickly when half the money has just disappeared, to focus on salvaging as much as possible.
Exactly. It's not whether Bitfinex is able to prop it up, it's whether Bitfinex thinks Tether can be propped up without too much expense. At a certain point it no longer becomes worth propping up, and that number is very far from the current $74B market cap it's currently at.