This was the part that I didn’t know about:
3: Wal*Mart will demand a higher discount.
Discounts in the US must be offered to all accounts on equal terms, by federal anti-trust law (such as the Robinson-Patman Act of 1936). There was a major lawsuit on that very subject in the 1990s, when the American Booksellers’ Association sued a number of publishers over terms.
That was the only part of his post I didn’t know about, but it makes sense. Check out the rest, though. It’s interesting stuff.