At least one of the Founding Fathers of India (who authored the Constitution) as well as the current Commander in chief equivalent are both "low caste" background, as are plenty of other high profile important folks.
The only reason the caste system exists is to enable reservations (kind of like affirmative action).
And finally, caste in and of itself was something introduced by the Portuguese. The original term was Varna, and it denoted your occupation/subject matter expertise. You could change your Varna, but usually you didn't do this because the opportunity cost was pretty high in the past.
However, all Varnas were considered important, whether it was military, trade, farming, or sweeping the street. I'm sure that there was prejudice, just as many on Hacker News in First World Western countries are prejudiced towards those in the Second and Third worlds, or a stockbroker may be prejudiced against the person making his McDonald's.