Why Brahmins lead Western firms but rarely Indian ones
What prevents someone in India who happens to have an unfortunate caste association to switch caste? Assuming family names are easy to change, what else is it that ties you to the caste? 
Or are family names what underpins the system so the whole system relies on that you <i>can’t</i> simply file some paperwork and switch to some middle-caste name if you were born unlucky?