Jews are the most clannish people I have ever met and the most prone to shameless nepotism (speaking as Jew).
I think Indians are even more so but there it's about caste and not just being Indian.
Humans are weird.
Alternatives like University Affiliation, Regional ties, Ethnic ties, Clan ties, and Workplace affiliation play a greater role due to the nature of South Asian immigration in the US (tends to be white collar professionals across all ethnic groups).
Treating South Asian Americans homogeneously will lead to the same mistakes like treating all Latinos homogeneously - plenty of South Asian heavy battleground counties like Loudoun County, Middlesex County, Williamson County, Kern County, San Joaquin County, etc have seen Ds margins drop significantly in the current election.
That said, we are a clannish bunch, and biradari (and every other South Asian language's equivalent of that word) is our guanxi.
That said I do agree with you to a certain extent that pre-Tech immigration absolutely was a thing (and a major factor in the Punjabi community across western US).
> more similar to Guyana. (My great grandfather came during that 1920s era but jumped ship in NYC instead
Oh dang, that's pretty wild! I thought most immigration to Guyana from South Asia during that era was primarily from Eastern UP, Bihar, and West Bengal, not Sindh/Punjab.