Borderlands competes with Amazon, so a 10% price hike means they are much less competitive, plus books have prices on their covers from the publisher.
You make several statements I can take issue with, but the most interesting is to imply that if someone else makes more money, other people are devalued.
I think that's an interesting argument in a world where executive compensation has grown continually, and workers income has decreased, while GDP has continued to shrink. http://www.epi.org/publication/ceo-pay-continues-to-rise/