Having run a business (in an unrelated field) that offered both a subscription and a paygo model, the reason was pretty clear: you lose more from people who wou

Having run a business (in an unrelated field) that offered both a subscription and a paygo model, the reason was pretty clear: you lose more from people who would have subscribed opting for paygo than you gain from people who would never subscribe but would choose paygo. The subscriptions are surprisingly valuable. Paygo not so much. Usual caveats apply: on average, in my experience, YMMV, etc etc.