On what grounds do they need to join any alliance .
Fact is right now the alliances appear to damage the smaller players more than help and is evident in Europe where being a feeder and receiving x in the € means you go broke moving other carriers passengers.
Better doing interlines where possible and taking the bulk of the ticket value in my opinion.
At the Manilla end they would only offer a limited range of domestic services anyway.
And again if they were to join say Skyteam they would probably see leakage over Seoul whilst *A they already have Singapore and Thai taking passengers away from them.
Oneworld has Cathay very active in the market place and Emirates/Qatar and Gulf Air all to contend with .
So what benefit joining an alliance = Loose even more potential revenue.