You must mean central Asia, not east Asia. To east Asia, flights always go across the Pacific, even from the east coast, so Asian carriers are typical.
Nope. I literally flew from ASEAN to the East Coast a week ago. The only options below $1400 round trip for economy were Doha (Qatar), Istanbul (Turkish Airlines), and Dubai (Emirates)
Korean Air and JAL have handful of direct options from NYC, BOS, and DC, but they are very marginal and appear to be prestige routes.
In most cases you have to either fly to the West Coast, or fly to the Middle East if you want to go someone that isn't Incheon, as the Incheon to X hop becomes much more expensive than the Middle East to X hop.
Most airlines codeshare and piggyback off Turkish and Qatar anyhow because both are heavily state subsidized
Tokyo and Incheon has direct, but there is more to Asia than those 2. Every other airport requires a transfer, and even those are $1400-1600 round trip unless from NYC
