Bitfinex has a very profitable system with Tether (loaning USDT out, and earning 5-6% interest), so they're incentivized to keep it running as long as possible.

Bitfinex has a very profitable system with Tether (loaning USDT out, and earning 5-6% interest), so they're incentivized to keep it running as long as possible. If they're smart, they have liquid reserves to cover the first x% of withdrawals. Which means - you would need something like a large drop in their backing assets (crypto, commercial paper, etc) + a confidence drop in the system large enough to cause a run on the bank, burning through all of their reserves. If no catalyst like this occurs, the game could easily continue on for years.