Recent noises from US telcos look to be putting Net Neutrality in danger. Net Neutrality is where all network traffic is treated equally but telcos are now sounding out the idea of getting ISPs to pay extra to have their traffic prioritised. No doubt BT are keeping a close eye on any precedent set here as it would provide them with a very healthy extra revenue stream.
If the telcos manage to charge the ISPs then who are the ISPs going to charge? If they simply up their price across the board then users all users will be paying the same price for a service of different quality, depending on what network their on. If they decide to only pass on the charges to users then the ISPs will have a billing nightmare. Users might also be tempted to move networks which would lose the telcos revenue too.
This move might also reduce progress on the advancement on the network. Instead of finding the extra network bandwidth needed to meet the demand, Telcos would simply be able shift the prioritisation of traffic around so that non-paying data is reduced to the slow lane.
And what happens when the data crosses multiple networks? As a chain is only as strong as its weakest link, a network is only as fast as its slowest point.