If that logic is allowed to take hold, consider this: Would it make sense to charge a smarter person more for reading the same book?
For example, if a college professor reads a book, and then uses the knowledge gained to teach, that reduces the value of the book (assuming the professor doesn't then use the book as the textbook for a course).
>>breadw+(OP)
It might make sense as a theoretical approximation of the value proposition. But you're going to piss people off if you try, so it's probably not a great sales technique.