Well…no. They have assets. They generate an income. Even if nobody wanted to own the shares and the price fell to zero, they could liquidate everything and pay out investors the cash (which is why the price will not go to zero, barring a dramatic downturn in business)
Must read for anyone dabbling:
https://crypto-anonymous-2021.medium.com/the-bit-short-inside-cryptos-doomsday-machine-f8dcf78a64d3
In short, Tether is manipulating the Bitcoin price and appears to be a massive fraud