--yet they're now in the lead.
The US used to have comically racist anti-Asian immigration laws, most notoriously the Chinese Exclusion Act. During the Civil Rights Era, these were replaced with merit based immigration laws. Combine that with the massive destabilization taking place in Asia caused by the Cold War and the rise of communism, and you end up with a mass influx of skilled, educated Asians into the US. Asian-American prosperity is the product of a historical fluke, not anything in the way of racial or cultural superiority.
The "hard-working Asian" stereotype is a lie. The American right likes to use Asian success as a cudgel with which to denigrate Black-America and pit Blacks and Asians against each other, but it's all based on lies and a lack of historical context. Google the "model minority myth". A lot of articles and books have been written about this topic.