I'm fully aware of how it works. I even said carriers make up their initial loss with service earlier in this thread. Goodbye thread.
That's the thing...they aren't charging you just for service on a contract, all the major carriers except TMobile direct (this still is happening for the third party resellers of TMobile) are basically charging the remaining average cost of the "$200" phone you're getting over time. Just look at ATT, Verizon, and Sprint compared their own prepaid offerings.
ATT GoPhone: unlimited talk and text, 2GB data = $60
ATT Data Share contract: unlimited talk and text, 2GB data = $95
ATT Individual Line: 450 minutes, unlimited text, 3GB data = $90
Verizon prepaid: unlimited talk and text, 2GB data (no LTE) = $60
Verizon contract: unlimited talk and text, 2GB data (with LTE) = $100
Sprint Pay As You Go*: unlimited everything = $70
Sprint Unlimited My Way: unlimited everything = $80
*you must buy one of the four approved phones up front
(everything calculated for a single line plan as that is the only fair way to compare to prepaid)
The Sprint numbers are closer together than expected, but what could possibly justify $30+ upcharges monthly from ATT and Verizon for service on a contract VS their own prepaid offerings? It's just roaming agreements, making up the remaining cost of the device that was sold up front (and this is where openwheel is arguing there isn't any real subsidy, just a loan in disguise), and pure profit (and in Verizon's case LTE access as a feature). Even then, TMobile still applies their roaming agreements to postpaid and their prepaid VS postpaid prices are the same, taxes/fees aside.
Just because the companies don't explicitly say that's what the extra charges are for doesn't mean that's not what they're actually doing. It's big business as usual.