I am still trying to figure out what the basis of the lawsuit would be? There is no guarantee that there will be a new iPhone every September, all Apple promises is that after 12 payments on iUP you are eligible to trade your phone in for a new one. Which you are, if you made 12 payments you can go to Apple and upgrade to a newer iPhone 11.
I'm with you.
Who in their right mind would invest the time + energy into challenging the terms of the upgrade program? If you're part of this type of financing, then you've agreed to terms laid out by Apple. I haven't looked at the details, but I doubt there is any language that would guarantee the availability of future unannounced iPhones to members.