The article is interesting (it was announced by the company that runs Incheon Airport). It mentions the PDX-HND flight and then says the PDX-ICN flight is "expected to be the only direct route connecting the Asia-Pacific region and Portland" (Google Translate). I wonder if Incheon Airport or South Korea offered a subsidy to switch the flight over, or whether Delta wants to use the Haneda slots for something else, or would otherwise have difficulty reducing 7x/week slots to 3x/week slots.
I'm trying to reserve excitement until Delta confirms it. The article (or rather the press release by the airport) says as if PDX-HND won't come back but it's only temporarily suspended. For a few months, though, PDX-ICN will be the only nonstop to Asia from PDX, since HND won't resume until when the winter schedule begins.