[jaclaz]

There are (since several years) "bus" electrical systems, simplified, there are five wires (live+neutral+earth+a two wire "bus" ) going everywhere.

You can decide to mount in "box #1" a switch and (say) a socket, then you configure the switch in "box#1" to command light bulb #23 and the socket to be either always on or commanded by switch #18, etc..

What you are proposing is essentially removing the two wire cable to go wireless.

You need anyway the three mains cables (live+neutral+earth) to get everywhere and passing in the same pipe/tube the additional two wires cable is "no cost".

NO practical advantages, but a whole new possible sets of malfunctioning and/or vulnerabilities.

Apart from the added (and not-so-trivial) added cost of a "bus" system as compared to a traditional electric cabling(not that your dream solutions will be any cheaper), the existing solutions work, and work reliably, because by now they have existed and have been tested for many years, let's introduce a new wireless protocol and brand new microprocessors/terminal devices that offer no advantage...