“This change aligns the upgrade date with the contract end date and is consistent with how the majority of customers purchase new phones today,” reads a statement from Verizon Wireless. “The first customers impacted by this change are customers whose contracts expire in January 2014.”
As the Wall Street Journal points out, it had previously made sense for Verizon and others to offer early upgrades to customers because it often meant getting them off standard calling/texting plans and onto smartphones, where the company gets a higher subscription rate. It was worth the cost to Verizon of subsidizing the purchase of that new device.
But now that many people are upgrading from one smartphone to another, an early upgrade just means that VZW is seeing less of a return on the often pricy device subsidies.
T-Mobile recently got rid of all phone subsidies, while also allowing customers to spread out the purchase price of their device over the course of up to two years.