People move to piracy due to lack of affordability and options.
I am from one of those countries where we pretty much cannot afford "legal" content. In my shitty town the median salary is something like $300, at least half of which goes towards paying rent if you don't have your own house, while we're being asked to pay prices that were established for developed countries with median salaries at 10× of ours or above.
Steam is one of very few exceptions and it's really popular here even among students and such (just like everywhere else).
Basically, if you want to charge me $50 for the book, you're not losing anything, simply because I cannot afford it anyway. Imagine if you had to pay $500 for books, $600 for movies, etc.
For example, The Pragmatic Programmer costs $10 in Indian stores, while it costs $50 in US.
Not making a moral judgement, just adding color.