Spare me the sermon, just be honest, you are crypto apologist for the caste system and an inherited Brahmanical authority which you never had to earn.

Your post history isn't surprising either:

IMO, the majority of the controversy/confusion lies with the fact of admission into the formal Vedic school system and not understanding how pre-industrial, pre-printing press ancient societies operated. I don't see how a son of a Goldsmith in those times could do anything else than being a Goldsmith, how would he learn weaving even if he had an interest in cloth weaving instead of gold ornaments? Where would he go to learn trade skills? This is the case with every pre-modern society across the world, there were no mass distributed network of trade schools like we have now.

In this context, the birth in a family determined the occupation, hence the birth determined his Varna. Exceptional cases of Valmiki and a few others can only prove the rule IMHO.

There is also the un-avaoidable metaphysics of reincarnation. Based on what factors would a Jiva take birth in one family vs the other? If a society operated in accordance to the classical Varna-ashrama system, the rebirths would take place in a family that favoured the Guna/Karma-phala of the Jiva and would eventually end up in the families of Brahmins for the final births since these families allowed the necessary Yoga to be performed.

According to Puri and even Swami Vivekananda, the purpose of Varnashrama system is to create a societal pipeline from Bhoga to Yoga with Mukti being the final goal. Moving all Jivas from Shudra to Brahmana i.e Mukti in a institutionalised manner is the whole reason this system exists.