Zero shareholder value was the overwhelmingly likely outcome, but not completely certain. (If Hertz magically recovered from bankruptcy, however unlikely, the payoff might have been >1000%).
The prospectus clearly stated that there was negligible likelihood of return.
On the flip side, from the creditor's perspective: "We loaned you a bunch of money, you can't pay it back, and there are some people who would like to buy shares in your company today? How can you not sell it to them?"
The unsecured creditors in this situation don't appear to be investment banks, they appear to be auto repair companies, perhaps exposed to counterparty risks from transacting with Hertz[1].
Your question brings to mind part of an exchange from one of my favorite pieces of financial cinema [2]:
SAM ROGERS: And you are selling something you know has no value.
JOHN TULD: (cuts him off cold) We are selling to willing buyers at the current fair market price, so that WE may survive, Sam.
SAM ROGERS: You'll never sell a thing to any one of them again.
JOHN TULD: I understand.
SAM ROGERS: Do you?
JOHN TULD: Do you!!! This is it, Sam, this is it!
[1] https://www.repairerdrivennews.com/2020/05/25/hertz-will-con...
[2] https://www.youtube.com/watch?v=7prnY2FOxns