It is all nice and good and well presented theory. Moreover, most likely it does work wonders for big supermarkets. However, back to reality:
It is highly unrealistic that they may hope it is going to work for them as well as it does for high street shops. 74% off!!!
Sorry for being very sceptical about it.
Another point. Low popularity, hence low selling volumes, hence higher price issue.
We are talking about e-Book. Once it has been created, there is zero cost involved in reproducing it. Zero. You cannot apply to it the same theory as you apply to any other product out there. There is no loss of profit for making 100 items but being able to sell only 20, thus having high price to compensate. Even s/w requires a blank CD to burn it on.