One of the main objections to micropayments for APIs is the cognitive load it places on the user. Having to think about 1-2 cent payments places a measurable cognitive load around usage compared to simply paying up front say $10 for certain access rights. Whether the cognitive load translates into the AI-realm is still to be seen and becomes a barrier to the success of micropayments for APIs. Another consideration is the fair exchange of payment for services received. It is in the business interests to charge for as much as possible including resources that will not be used. On the other hand, users, want to minimise their payment and only overpay so much so for added convenience. Cognitive load + unbalanced fair exchange is what led to the status quo. Will it be fixed in the AI-realm? Not sure