Its called a razor & blade business model. Canon are in this type of model, not even cameras, but their printers too. Cheap printer, expensive ink.
Its is fine for them to sell the camera body cheap to you, eventually you will need better lens as it poisons you. So what if an individual refrains from using their better quality lens? There are tons of others who buy it because of the "Canon" name stucked to the product, or the red ring of the L lens. Some people believe in paying a premium, while those who don't believe will not get to enjoy it.
If you look at the TS who has cycled thru all the different cameras, can you believe if he has nvr made a single lost whenever he resold his product?
Of course its good for TS to share with others how to get discount thru canon's beyond economical repair program, but how many would really go thru all the trouble to save $350? If you are into DSLR, you will be clear of the high cost of initial investment, and prob wouldn't bother.