Do Ethnic Power Blocks Just Make Sense?

Small numbers of tightly knit ethnic groups - as long as they are well educated and industrious, seem to do better than the indigenous populations. The Parse in India, Jews in Europe and the US, Indians in the US, Chinese ...everywhere.... even seemingly similar peoples - the Scottish are and were disproportional represented in parliament, as Prime ministers and were the doctor/lawyer class in England.

Perhaps resisting assimilation is more an economic model than a cultural one? Or do they have an advantage, like a global corporation with no interest in the welfare of locals? For example, my fairly educated WASP family devotes much of its time and resources into money losing pursuits like natural and historic preservation. Obviously an immigrant family, generally speaking, did not move here to save the local species of warbler. If the assimulate, chances are they will start to take interest into the long term well being of an area. A migrant peoples, by definition will not.