It will be interesting to see how this plays out. Delta fumbled SEA. Given its investment I can not imagine DL did not run risk scenarios and see AA/AS/oneWorld coming. There is no way SEA can support hubs for AA/AS and DL. Barring AA having to significantly shrink, DL will have to retrench, at best making SEA a focus city, and place more network emphasis on LAX.
AA should be well positioned in SEA with AS, CX and JL to be extremely successful. If AA can’t make SEA work, the whole executive team should be ousted. Was anyone at DL ousted for its SEA mess?
When DL ended the relationship with AS, the word from AS is that they were essentially being "blackmailed" into being DLs sole partner. From DLs perspective, it was that they couldn't control pricing on the AS legs and AS wasn't offering them enough feed because of all the partners it's trying to feed at SEA. I honestly don't see how AA isn't going to run into the exact same issue. Absent a JV or merger, AA can't control AS' pricing and can't have leverage over how many seats are allocated to AA connects vs. JL, CX, SQ, etc. connects. It's entirely possible we're about to see AS/DL 2.0 here. I think people are getting way ahead of themselves calling AAs moves in SEA a roaring success when not a single one of these routes has even launched. I'm sure DL did the risk analysis, and I'm willing to bet they were well aware that AA would partner with AS, but given their own history with AS, it was a risk they were willing to take.
They have struggled sustaining long haul to Asia to even large markets like HKG and KIX. Except for ICN and possibly PVG, AA/AS will have a huge advantage over DL from SEA, and double the market share (and number of routes?).
As another poster noted, HKG yes, but everyone, including the Japanese carriers, has struggled to make a go of KIX. Only UA with SFO has been able to sustain long-term service. HKG is an interesting case, and people seem to completely overlook some very important facts. Not a single US airline, not AA, not DL, not UA has been able to make LAX-HKG work. Up until a few years ago when DFW-HKG was launched and when CX expanded into places like BOS and SEA, HKG had only been able to successfully maintain TPAC service to the big 4 US TPAC destinations (ORD, NYC, LAX, and SFO). HKG is obviously a very tough nut to crack. UA has succeeded there (and even they had to drop ORD) because they serve HKG from SFO and NYC. Besides, I think people overemphasize HKG. It's a single city in Asia. It's not the be all, end all of Asia service. Plenty of airlines do not serve HKG and survive just fine. DL isn't going to collapse because they don't serve HKG. But besides those two, where has DL "struggled" to maintain longhaul to Asia. The DTW routes have been flying constantly since they were launched. Same for the SEA routes sans KIX and HKG. DL has never retrenched from PVG, PEK, NRT/HND, or ICN, so I'm having a tough time understand how they're struggling.
I still think we're getting way ahead of ourselves here. See above. Let's see how the AA/AS relationship actually works out. It's entirely possible we're about to see a rehash of the AS/DL relationship.