First - I am sure you're "pleased" that MR gave this document fair time. right?
Second - Samsung isn't alone in using carrier incentives. There are two models it appears.
Apple - "forced" a large contract with a guarantee on # of phones purchases.
Other OEM - provide incentives in way of higher commissions, etc.
Personally - I wouldn't like to be a carrier store manager. Thing about it. On one hand - you and your staff can make a lot of money by selling Android and employees are happy. On the flip side, your bottom line is being dictated by the carrier who stands to lose a lot of revenue if they don't make good by selling the contracted Apple products.