You're incorrect.
The 2003 concessions were sold to the AA employees in part because they "saved the pension." While you did get several more years of accrual (years of service), the beneficiaries of "saving the pension" were the pilots. They're the only group (other than management) whose pensions exceed the PBGC monthly maximum guarantee.
The level of underfunding when AA finally filed Ch 11 was irrelevant except for the pilots. Gotbaum argued to deny AA the same benefit afforded to UA, DL and US, all of which terminated their underfunded pilot pensions. Since it was underfunded, the PBGC would pay only up to their monthly maximum. And unless you're a pilot, that was very unlikely to affect you.
Now, AA has a cash obligation that requires real cash every year but doesn't make your pension any larger than it would have been if AA had been permitted to terminate it and turn it over to the PBGC. Those pension contributions (like all expenses) are cash that AA doesn't have to pay you.
Termination would have sucked for the pilots, but termination wouldn't have changed your benefit. Your frozen benefit is going to be exactly the same as it would have been had the pensions been terminated.