T-Mobile abruptly stops offering JUMP! On Demand lease option for new customers

T-Mobile recently pulled the plug on the JUMP! On Demand leasing option when upgrading or signing up for a new line. Current JUMP! On Demand customers won't be switched from their current plans. So they can continue to switch phones anytime they want to, up to 3 times within a 12-month period. T-Mobile must have used this tactic to gain a ton of customers. Surely the only way T-Mobile could have possibly made money with JUMP! On Demand customers was purely on service. Offering this kind of upgrade as frequent as JUMP! On Demand had was just not cost-efficient for a long term...