1) Getting a movie the legal way is much slower and harder than getting it in a few minutes at the comfort of your room
2) There will always be people who don't want to pay for movies.
Now to talk about India specifically, the first point breaks down. Our internet speeds aren't really high enough to promise that a movie download is faster than taking your bike and renting the DVD for ₹25-50 nearby.
Regarding 2), we find that people have no qualms buying tickets at theaters for > ₹100. Buying DVDs however is very rare, at least among the average Indian populace.
So unless we find a middle ground piracy is still going to happen. And frankly, I think we have much bigger problems than piracy to tackle.
Just my ₹2