You may know that Vaidika peoples were not all that keen about vegetarianism, and animal sacrifices were common in pre-Buddhistic times. however, with the advent of Buddhism, all this changed, and the Buddhists brought into effect draconian laws against animal slaughter, and against trades that brought suffering/death to animals.
Of course, people could not stop wearing or requiring leather, or stop eating meat completely, especially the people who earnt their living by manual labour. therefore, like the Burakumin in Japan, people who were associated with occupations such as butchers, undertakers, tanners, leather workers and also people who used to engage in hard manual labour and therefore consumed meat on a regular basis were automatically relegated to a lower section of society, and were disparaged by the Buddhist elite.
India is not the only place where this has happened, this has happened in Japan also.
Colonialism and census
The British, with their propensity to mensurate everything, crystallised the caste system even further, and codified it into what it is today.
Earlier there were no regional divisions in castes, only divisions based on actual practicality.
When I say the abhivaadaye, i only mention my family's gotra, pravara, veda, suutra, shaakhaa and finally, only my name. Not even my last name. Not even my father's name.
However, according to the British census classification, I am classified as a deshastha rgvedi marathi Brahmin.
This caused the caste system to be further stratified, creating sub-divisions within sub-divisions within sub-divisions.
Reservations in modern India
Today the caste system in India is being perpetrated because of the reservations. The forward castes use it to 'show' how the backward caste people are inferior to them. The backward caste people clamour for more reservation as a large majority of the backward caste people are not receiving any benefit of the reservation system, since the same creamy layer amongst the backward castes and its progeny are enjoying the reservations.
What do you say?