I agree with much of what you say. AA's overall costs may very well be lower because of its overhaul operations. But that doesn't mean that management wouldn't have followed that herd and closed TUL and MCI. Laid off thousands of employees at those bases.
On the subject of filing for Ch 11 - why do you think the company lied? US, UA, NW and DL all filed for Ch 11. Had the concessions not been deemed accepted (I realize many don't think they were approved by vote), do you really think AA would not have filed? If so, why not?
About UAL - I agee that it probably isn't saving as much as everyone had hoped by outsourcing all heavy airframe overhaul. Same with its new Defined Contribution retirement plans - AA's DB plans may still be cheaper for AA.
About the A300s and MD-80s? Grounded and replaced with nothing. AA would likely have shrunk even more than it did. In retrospect, given $2.00/gal+ jet fuel for the last two years, dumping them might have been a good idea. Of course, had the lessors agreed, maybe AA would have kept them for much smaller lease payments.