There's almost certainly not enough O&D demand, but with the JV it can work. No Asian airline flies to PDX and the only other flight to Asia is DL's flight to Haneda (which is mostly point to point as DL has no partner in HND and their main TPAC hub is SEA). So it's really about serving all of PDX's Asia demand other than Tokyo (since DL is already flying that) and mainland China (not covered by the JV). Portland has a lot of sportswear companies with a presence there. Obviously there's Nike, but also the US HQ of international companies like Adidas or Li-Ning, and also offices of US sporting goods companies that are headquartered elsewhere. While corporate offices are heavily concentrated in PDX, the manufacturing is entirely in Asia. A lot is in mainland China but there's also plenty in Southeast Asian countries like Vietnam or Malaysia. If you live and work in Portland, you're likely a DL flier, and how do you get from the corporate office to the manufacturing facility? The easiest way is to fly into ICN and then connect on KE into those destinations