Check this out.
United: Gets to either ditch the Pinnacle contract that isn't going to be flown and take those planes and either farm them out to somebody else, or in the worst case, return them to the bank. In either event, United isn't on the hook for anything. In the best case situation, United is able to take those aircraft and move them from carrier to carrier as they see fit. Companies do this kind of stuff all the time, see FedEx with their fleet of Caravans. Additionally, in leasing the aircraft from the bank, and then subleasing them to another regional, they get the tax advantages of having a lease vs. an aircraft own outright.
The Bank: The bank gets to get their hands on a hot aircraft that is selling well around the world. SOMEBODY will want the aircraft, whether it's United or another carrier in this country or another one. Because it's a secured interest, they'll be able to sell it for cash if, somehow, they can't get the thing to fly for somebody. What do you think Q's are going for right now? I'm willing to bet there isn't that much of a mark down because they're used, and thus the aircraft are little more than an investment that'll either pay a dividend by being leased, or they'll be a safe, yet low yield investment for their cash. These guys make out like bandits, basically.
Pinnacle: Gets to ditch an unprofitable part of their operation and right size the company towards the types of operations that will make them the most money. Instead of getting the 7% from the pilot group, or whatever they're asking for, you get rid of part of the pilot group. Problem solved.
The Pinnacle Pilot Group: Gets screwed.
How is this NOT exactly how every other financial transaction in this industry has ever worked? The bank makes money, the company makes money, the pilots lose.