If you listen to their shareholder calls, the big 4 (now 3) say they view the $30 upgrade fee as a way to offset the 0% interest rate monthly payment plans. In other words, the payment plans are not really 0% because they require an upfront $30 fee for the loan. But if you buy the phone outright, then all you have to do is swap the SIM and don't pay that fee.
Not trying to justify it. The $30 fee is 100% bullpoo, and it's just the peak of the bullpoo fee telco mountain. Just giving context to how the telcos see it.