Caste comprises an important component of a person's identity here. It's a hereditary, communal-level identity.

But the level of relevance of a person's caste in a particular region in India differs based on how urbanised and economically mature the place is. I'd say that it is becoming increasingly irrelevant in Tamilnadu because of the economic growth we've witnessed in the recent decades.

Perhaps you mean caste in terms of economic strata. (Class, I guess?)

Either way, I am trying to think how a libertarian society would deal with this stratification and provide a challenge to existing hierarchies of caste or class.

Reg 'Bitcoin fixes this', I agree with you that it would play an important role.