"There is a general consensus that ultimately photons will replace electrons running through wires in most of our microelectronic devices."
No there isn't.
We know that for silicon CMOS, Moore's law is starting to slow down and further miniaturisation is becoming much more expensive. We know that if the complexity and efficiency of microelectronics is to continue improving at its current or past pace, we'll probably have to move to something other than silicon. There are multiple possibilities, including carbon (graphene or nanotubes), semiconductors other than silicon, titanium dioxide memristors and other more exotic things. Maybe one of these technologies will enable us to push computing closer to its physical limits. Maybe more than one. Maybe none of them will, and eventually we'll just have to be satisfied with gradually refining and optimising silicon CMOS techniques even further. Optical computing has attracted some criticism about its prospects: http://www.nature.com/nphoton/... (sorry for the paywall).
There is no consensus at this point that any particular technology, optical or otherwise, is one of the next major steps in microelectronics.
I think the point that was being made is that optical will eventually replace all electrical connections. It was not saying the only jump to be from Silicon -> Optical, but rather will ultimately be replaced by Optical as a faster medium just like the advances we saw by deploying Fiber Optic cables (and the more recent push for optical-based network switches to replace existing electrical). Realistically the full Optical transition is still years away and you are likely correct that we will move to on of the other transitional architectures that are still electrical-based in the mean time.