When the world move on to 4G and 100Mbps. Some question why do we need such a fast internet speed. Simply because there's a demand and a need to keep advancing and moving on.
Thus, when we upgrade to 1Gbps. Others would be questioning the same thing, so will they when 2Gbps is available.
We are confidence of providing 1Gbps via wan network. However, bottleneck such as wireless network, hard disk slow write, homeplug and many more will always exist and may potentially slow down .
Under best case situation with the correct devices. Full speed is possible.