I think the answer is, that in sexual matters part of our brain is hardwired to attach to individual humans. Subscriptions create an incentive to keep consumin

I think the answer is, that in sexual matters part of our brain is hardwired to attach to individual humans. Subscriptions create an incentive to keep consuming a particular resource, you don’t need that incentive if your audience already gets an oxytocin/dopamin kick just from seeing your face. The other industries that got that right are far more morally questionable than pornography: Big Pharma and computer games.