Alec Mowat :
And you don't need a massive infrastructure change. People have been able to push 1 TB over the current fiber infrastructure. It's not the cost, necessarily. It's the desire for change when ISP's are making a fortune nickle and diming.
If you read your own link, they aggregated multiple 200Gbps channels to reach that 1Tbps. 100Gbps hardware is not exactly cheap and speeds beyond that are not quite standard yet. Those are not going to become commodity speeds any time soon due to hugely expensive hardware - if you fit a Brocade, Juniper, Cisco or other router with enough cards and optical modules to handle 1Tbps, you are looking at a bill over 1M$ at each end for the routers alone and you still need to add all the optical gear to merge those 10/40/100Gbps streams into a single fiber.
At the more realistic end of the range, 10Gbps hardware is starting to approach commodity level.
Just because it can be done with current hardware does not make it economically viable.