> If Bob eventually pays back and the bank doesn't make any further loans, the bank will have 1$ (my dollar) and a couple of cents of interest.
This is wrong. The bank will have $1.90 + interest. You have to pay back your entire loan. Yes, bob might default, but averaged out, the risk calculations set the interest rate high enough to cover that profitably. The fractional reserve part of the banking system is a temporary choice that happens continuously. But if stopped, the bank would eventually have all of its cash because it has all of its reserves covered in debt.
> If I give Tether a dollar Tether has another dollar. I get a Tether token which I can exchange on the open market for whatever the market price is. It supposedly is possible (though inconvenient) to get Tether itself to exchange their tokens for actual dollars (of which they hold only 70%) but (just like a bank) Tether relies on that not happening "at scale".
The difference is tether has no title to the missing 30%, and probably even more of it if we are going to be honest. The likelihood of repayment and the fullness of reserves are two separate concept. And banks win on both counts.