I don’t think “subsidizing” is the right word as the customer still had to pay for the full price of the phone. The carrier would just spread out the cost of half of the phone across a 2 year period.

Nowadays (at least for Verizon) you can get a phone for nothing upfront and have the entire cost spread out over a 2 year period. Basically the same as before except it requires nothing down instead of half the phone value. If anything I feel this method is more likely to get people to sign up as it requires nothing upfront.