A bad book and good marketing won't work, the same way a good book and bad marketing will also not work. There is no choice in the matter that if you need to write a good book, you also need to have good marketing for it.
I think it's a fallacy to say that a good book sells itself. It doesn't happen. I'm a voracious reader and I can give you a long list of books which should have been best sellers but they aren't. How can you buy a book if you haven't heard of it?
The good news is that a vast majority of Indians from different religions see no contradiction between religiosity and liberalism, keep India stable. We religious liberals don't talk loudly enough.
Anuj Bahari has always been a really good literary agent for me. What a good agent does is that he manages many of your business aspects so you can keep your time free for writing.
A person's ethics and character are not tested in good times. It is only in bad times that a person shows how steadfast he is to his dharma.