Think of it this way: there isn’t nearly enough demand right now, regardless of whether you (the dealer) discount your inventory or not. I.e., you will not move enough cars to pay for fixed costs like the mortgage on your building, financing the inventory on your lot, etc. The Fed has done various studies on household savings account balances and/or net worth (https://www.valuepenguin.com/banking/average-checking-accoun... and https://abcnews.go.com/US/10-americans-struggle-cover-400-em...). The vast majority of Americans would have to finance a car purchase, even for something like a 10-year old used car. Yes interest rates are low right now, but does it make sense for a consumer to buy a depreciating asset and increase their monthly interest costs at this point in time?
To the car dealer (or rental operation like Hertz), the question is does it make sense to have a fire sale on your inventory now (at prices that will almost certainly lead to an accounting loss), or do you take your chances in bankruptcy court? If you believe that in the next year or two that the market for used cars recovers somewhat, you can sell those assets off during bankruptcy proceedings to pay off creditors etc. There’s a strong case that taking this approach will leave the company as a whole better off in 3-5 years, though equity holders will certainly be taking a huge hit.