I'm willing to accept that but I think it would still lower the amount of income significantly. Sure people would still pay for custom porn or specific clips that are hard to find (though even then I'd suspect quite a bit less than they do now), but they probably wouldn't join any subscription based sites for example.

As I understand it, this is less about subscription based sites and specifically about cam models on pornhub. While I agree that this extra step would be a barrier to a casual consumer, I agree with the parent that people who pay for porn will pay for specific porn. if a person is already paying a specific model (or models) on pornhub, they've found what they want and a fair amount will continue to pay for it even if it takes additional steps.