This varies between diaspora communities. Some keep a closely knit community to safeguard their interests across class divide like Jewish groups in U.S. !?
What you're saying is particularly true for communities from subcontinent - one who becomes affluent and influential sucks up to their superiors, and keeps those gates closed for others, discriminating against their own kin.
That's literally how Indian subcontinent was colonised. For some reason there is much sympathy for subcontinent as victims of colonisation (rightly so) while others like Palestinians are a 'tricky' matter like they also were complacent for selling lands bullshit etc. While the reverse is actually true, these fuckers themselves tempted Brits into their politics, competed to lend them money and consciously choose company rule over other options.