Comparing CPU frequency (tens of thousands individual lanes that have to be skew-matched) to single-path stuff is quite apples to oranges. Processor frequency is mostly limited by interconnect and cooling (and silicon, but there are other materials available, it's just not worth switching to those unless you solve cooling). Even thunderbolt transceivers go 40GT/lane=20GHz and that's consumer tech. With InP you can go slightly above 100GHz afaik.