You have a big office of 3 Floors or a Home which is not Wi-Fi Friendly and it does not have the provision for LAN or any other wiring. Even a distant room/garage or basement beyond the Wi-Fi range.
Wireless Gigabit Alliance - WiGig 60 GHz
If we could build a Wired interface for Wi-Fi and WiGig then such rooms can be brought within range. A wired interface without wires, then you think of optics, not even optic fiber .... that will build up the cost for home networks.
Wave Guide may be an answer, a wire that pretends to be a waveguide. Let us take a thin flexible plastic tube, 2-3 mm in dia, 1mm wall thickness of tube. The outer wall of the 3mm tube is coated with a suitable copper alloy. Above that a thick insulation to protect from mechanical damage. This may act as a waveguide if properly designed, probably the way or pattern in which the metal is coated.
Fixed WiMAX SoC and RF Module - Fujitsu
If this works in theory, then Pump RF on one end with a little more juice, just like in Optic fibers. The other end may get enough signal strength for good speed connectivity. It will at least be still wi-fi on waveguide and easier to implement than RJ45, these LAN cables, connectors and switches include many components and modules, that make it very fussy and unreliable.
Wi-Fi seems to be very friendly and safety has also improved now. So a wired, one wire or waveguide to extend Wi-Fi can phase out the RJ45. I like RJ45 similar to the sentiments i have for the Printer Port and RS232. Then USB has just taken over. Change is inevitable, Find a way out of RJ45 for good.