Vast amounts of content are delivered today on overlay networks (again: we call them CDNs). Overlay networks have enabled the current scale of content delivery on the Internet. Your performance concern --- about an overlay design you haven't even sketched --- is worse than handwaving: it can be falsified even without asking you to clarify.
I wish you'd stop trying to make me defend the NAT service model, because that argument is extremely boring. My point, which I think sees overwhelming evidence from just a cursory look at the modern Internet, is that most users are not harmed by NAT. Innovation continues despite its pervasiveness. We should use the time NAT has bought us to come up with something better than IPv6, which continues to bake critical policy decisions into $60,000-$200,000 Cisco router and switch chassis.
I wish you'd stop trying to make me defend the NAT service model, because that argument is extremely boring. My point, which I think sees overwhelming evidence from just a cursory look at the modern Internet, is that most users are not harmed by NAT. Innovation continues despite its pervasiveness. We should use the time NAT has bought us to come up with something better than IPv6, which continues to bake critical policy decisions into $60,000-$200,000 Cisco router and switch chassis.