Any one of those backbone networks has far greater reach and capacity than the NSFNET at its peak. Take Verizon's backbone for example.
Backbone performance -- latency, throughput, packet loss, and jitter -- are improving exponentially. Here we see live reports of Verizon's backbone performance over time. They guarantee performance by giving their customers a service level agreement.
Researchers at Standford university track overall global performance and find dramatic improvement on international backbones.
As Ethernet improves, we increasingly see it being used to extend local area networks over "backbone" distances.
We have demonstrated that the Internet connectivity can have an important, positive impact on developing nations, and public investment in backbone networks is needed because the private capital markets are not closing the digital divide.
We have seen that new data types become commonplace as technology improves. Video is becoming mainstream, and video files are large. Demand for video combined with greatly increased access by mobile and portable devices is predicted to outstrip access network (not backbone) capacity within a few years.