You wouldn't expect him to charge $10 and receive only $5 per sale, would you?
If my game was on store shelves in ever major department store (WalMart/Kmart/Target) in the USA and was being directly exposed to millions of customers in each of the several thousand locations, I would jump at the chance to get $4 or $5 for each $9.99 game sold. You would make a ton of money. Most of the authors I know who routinely target this audience with their games are making low six-figures off of their games.