Actually not correct: most banks want to make sure their asset is being looked after properly, because how it is operated and maintained makes a huge difference to the resale value.
You're still missing the point. The banks stand nothing to gain or lose by the resale value...they are simply financing the note for the purchaser. If the purchaser turns around and sells the airplane for twice what he paid he gets to pocket that and the bank just gets back the loaned amount. The bank makes the most money if you don't resell the aircraft. If the airplane plummets in value the person who bought it still has to pay the full balance back to the bank....of course he may default and the bank has to come after him and will repossess the aircraft but likely the bank has secured other collateral as well as forced the buyer to guarantee the value with an insurance policy.
Maybe it works differently in Europe but I don't think so. You're probably thinking of a different scenario where the bank may have invested heavily in the company as a whole and has financed many aircraft and other assets of the company and may even own a significant stake in the business.
The bottom line is in this case the bank will have no liability or responsibility as to the operation of this aircraft.