Earlier quoted context omitted.
The median Asian income is easily explained - only educated/relatively rich Asians can afford to immigrate. Most immigration is relatively recent (60s to present) so their status hasn't really had time to change a lot.
Citation? There are certainly rich Asians who immigrate, but I know plenty of people who immigrated and are absolutely not rich at all. Many Asians who immigrate have little to nothing except an education, some don't even have that. We brought many over during the time frame of the Vietnam war who had nothing at all.
Are Indians included in Asians?