Family traditions well-educated them. Still, they are. They were ahead of others because they were the first people to adapt to Farsi and English before any low caste convert could do it. Most bureaucrats and admin staff of the Sultan/Mughals/British were, therefore, the Bramins. Even the Sultans relied more on the Brahmins than the native low-caste illiterate converts. Even today, education largely follows the family tradition with few exceptions. If parents are university graduates, the children are more likely to follow suit.