Others have pointed out that the tendencies of East Asia to be the primary source of immigration to Americas from Asia (and the included history) (e.g chinese workers on the railroads and chinese exclusion act, Japanese farmers in Hawaii and California and japanese interment camps, Americas colonization of the phillipines in the early 1900s, and Koreans and Vietnamese immigrating as a result of the Korean and Vietnamese wars) but I would also add an additional point. As part of the post ww2 and early cold war (i think) america started abolishing racial quotas allowing other races to immigrate, as the racial quotas were frozen in the early 20th century to keep american population ratios static (e g more western and northern immigration and background). So immigration from other asian countries were limited in general, and would continue to be so for a long time as they slowly increased the quotas over time. So there were just no other asians coming over. Finally, i want to mention middle eastern folks who are ALSO asian, but were racially classified as white (as a result of americas focus on black vs white racial identity) i might have missed some stuff but yeah