the answer has been posted a number of times but I'll try a quick recap....
AA/US is NOT the same merger as others. You and others want to argue that AA/US are being shafted because they can't get a merger now but others did.
By AA/US' own filings, they would become a larger airline that DL or UA even though they have a minimal presence in Asia. THAT means AA/US would be much more heavily concentrated on the east coast including in limited access markets like DCA.
It also doesn't change that there is documented evidence from AA and US execs saying that the purpose of the merger is to raise prices and reduce capacity - which is not only uncompetitive and sufficient to block the merger even if the network issues weren't a problem - but they also didn't exist with other mergers. There is no evidence that DL/NW, UA/CO, or WN/FL execs said the same thing.
Finally, the DOJ doesn't forecast profits for any industry. AA/US execs said they both airlines could be profitable on a standalone basis and AA just reported record profits to demonstrate that. If the Middle East melts down in war and airline profits tank, then perhaps AA/US can remove that objection.
It is absolutely true that the airline industry is highly cyclical and the up cycles are much shorter than the down cycles.
But AA filed for BK during a strong period to help ensure they can emerge and Parker went after them in BK.
The timing for AA's successful restructuring doesn't happen to align with the ideal time to be asking for a merger that will eliminate significant amounts of competition. The DOJ doesn't have to change its standards to fit Parker's opportunity.