I don’t think I have ever even once been in a product design session where the stated reason for going with a subscription model was, “So the customer can pay us less money.”
Even if the TCO for the clinic were exactly the same over X number of years, the manufacturer that sells subscriptions still comes out ahead because they're effectively in the financing business, too. Why tell a customer to go borrow money from somebody else when you can make them borrow from you?