The problem is that a max data rate usually doesn't some with an SLA. ISP's obviously don't have enough bandwidth for all customers to fully utilize 10 gbps 24/

The problem is that a max data rate usually doesn't some with an SLA. ISP's obviously don't have enough bandwidth for all customers to fully utilize 10 gbps 24/7, for example. Paying based on usage solves that tragedy of the commons problem and works for utilities.