I think Seattle is really trying to make those routes work, and that marketing push you saw is part of it. But I think they have lost more routes than us, even if they got a lot of new ones, some cancelled after not long. I know Delta axed a few, and I think a couple others too. This was just posted the other day:
Xiamen Airlines closes Seattle reservations from late-September 2019
By Jim Liu
Posted27 May 2019 07:30
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Xiamen Airlines in recent schedule filed service changes for Xiamen – Shenzhen – Seattle service, as the schedule listed until 25SEP19. Reservation for travel on/after 27OCT19 is also closed. The Skyteam member currently operates this route 3 times a week.
MF845 XMN0920 – 1045SZX1245 – 1015SEA 788 135
MF846 SEA1245 – 1800+1SZX2025+1 – 2135+1XMN 788 135
https://www.routesonline.com/news/38/air...e-reservations-from-late-september-2019/
This route was a stretch anyways for an airport like Seatac, but still, the pullout has to do with performance and not aircraft limitations. I don't think YVR has lost any of its Asian carriers since SQ in 2009 (and hopefully won't)
**Edit, also Oasis Hong Kong was also one, but the company went under, so dropping routes was what they did