I suppose I am going to get jumped on for this, but my cut on this is that "net neutrality" will happen, and is natural in a free market. Let me explain:
First of all, I work in a research group where this is a hot topic, so I am not a disinterested party in the matter. One of the topics that people/companies/organizations are always whining about is "performance" and "Quality of Service" (QOS). This can be defined and measured in a number of ways (response time, capacity, throughput, etc.) but for now let's talk about a topic of interest to users: response time.
Like it or not, society views some pieces of information as "more valuable" than other, particular wrt response time. Emergency services is the most obvious example, but there are others. Other issues involve corporate transmission of information - and the cost thereof.
When a router receives packets, it opens the packets, reads the "headers", and based on the info in the header and its current view of the network, forwards these packets along an appropriate route. Since zillions of packets are being processed, they are frequently dumped into queues and processed in some order. Obviously this order does not have to be "first come first serve", but can be processed according to some priority. Also, in principle, the routes can be chosen so that some traffic goes along a preferential route... etc. In a large complex network there are lots of routers and links of varying capacity/processing power, so there are lots of options for choosing the way packets go through the network, and the wait times for processing of these packets.
Given the ability to treat traffic with varying priorities, then the question becomes that of ethics and economics. As a "free market" kind of guy, I happen to believe that those that use more of a product or service, should *pay* more for that privilege. Now some people think that everything should be free, and that everybody should have a beautiful oceanfront home in Malibu. Not possible. So given that we are dealing with a limited resource (bandwidth, router processing capability), then my approach would be to let the market decide, within certain limits dictated by the laws of trust/monopoly. So we are talking about classic market economics in the various network proposals that do not "honor net neutrality", and building in protections so we have neither "mob rule" nor "robber baron rule" in traffic management.
I *know* I am in the minority on this, but I would like to hear peoples arguments on why "pay for performance" should not be part of the internet architecture at the most fundamental level - given that we build in safeguards...
and like I said, I am hardly a disinterested party....
Edit:
FYI: When you send a message like email, or view a website, the email/page is broken down into small bundles of information called "packets", and sent to the end-user. These packets are then reassembled at the receiving end where you view your email/page. So the big debate is whether each packet should receive some form of preferential treatment based on priority, like emergency or $ cost, within constraints. Looking forward to hearing both sides.