AS seems to be doing quite well and is much more consistent than the others so I'm not so sure that's a bad play.
AS' code-whoring isn't the "end all be all" of airline strategies. AS is highly dependent on the codeshare revenue that comes from sleeping with everyone. If you removed that revenue, AS would probably have some issues with AA, UA, WN and DL crawling all over their routes. Their last defense would be all the monopoly routes ex-SEA, and intra-AK.
Notice how AS has pulled back over the past year?
The code-whoring strategy only works if other players in the market are willing to curb their desire to fly their own metal and pour traffic into your network. How long do you think AS would last if AA and DL both decided to make SEA a hub?
With Delta's obsession about market share in JFK, I'm confident that the B6 execs realized that going it alone will prove costly. Better to turn AA/OW into an ally than to compete against both AA and DL.
LH and Star alliance provide little assistance in what is essentially a domestic turf war.