I knew that on other boards it wouldn't take long for someone to say "but LAX is a hub". I underestimated this board, apparently!

Just about all of AA / AA* flying operates from one of those five markets, with some remaining SJU service.

AA* is definitely being shrunk. In addition to San Juan reductions, there will necessarily be flying reductions which affect some or all of those five cornerstone markets. Just because a route serves one of those places does not make it immune.

Of those five markets, Los Angeles seems to be the one where AA* has the least connecting flow, and so routes largely have to primarily stand on local traffic alone. Unlike airports with a lot of connecting flow, they could cut unprofitable AA* flying without excessivly harming the overall operation. And a market like LAX-DEN, with CRJ-700's up against Southwest, United and Frontier mainline, might well be a bloody one for them.

Commonly when an airline retrenches, they fortify themselves in places they are strong, and retreat in places where they have been fighting an uphill battle. They dominate DFW and MIA, and have a huge investment in a connecting operation at ORD. At JFK they have a large international portfolio, and only a small number of AA* flights...so even if they wanted to cut AA* flying there, there isn't much there to cut. At LAX, they have a solid amount of AA* flying, much of which flies wingtip to wingtip against much larger mainline competitors. That include two LCC's focused on beathing the crap out of eachother. And that's why it wouldn't surprise me in the least if CR7/ERJ markets like LAX-IAH, LAX-DEN, LAX-ELP, LAX-ABQ and LAX-SLC, end up on the chopping block.

Of course this may not happen. But we've seen legacy airlines try to muscle into their way into markets dominated by others by putting in a business-friendly schedule of small jets. It can be a costly endeavor, and these sorts of efforts are often ditched during difficult times like those AA is currently enduring.