But India has a problem. India is one-third size of the United States or China, and they have 1.4 billion people and growing 2 billion or 2.3 billion is not going to work.

It's a civil hierarchy, but I doubt that's what GP meant by "caste system".

The USA has historically had a two tier system enshrined in law: one for "whites" and one for "coloreds". (There are two sets of bathrooms in the Whitehouse!) Just because the laws were technically repealed, doesn't mean that the system evaporated overnight.

Coloreds are still hugely overrepresented in the criminal "justice" system, they're still much poorer on average, are still disenfranchised en-masse through gerrymandering and voter ID requirements that accept shooters' club membership cards but not ID cards poorer blacks might possess, etc.

For all intents and purposes, the USA has a caste system that has evolved from an earlier system that was apartheid in all but name.