A more realistic reason is that many people just don't have the option of running cabling through an existing property - people who rent.
As someone who's never owned a structure but has had wired ethernet in every room of every place he's lived, I have to call bullshit. Sure, wiring is harder when you rent, but it's not impossible.
Some landlords actually welcome the improvements, seeing the value in modern connectivity, and allow more traditional wiring to take place. My current rental house is like this and over the month I've lived here I've spent an hour or two per weekend with fiberglass rods, fish tape, and a cable bit getting Cat6 from a patch panel placed in the office to the TV, bedrooms, garage, and anywhere else a permanent network device sits.
Others may not be officially interested in such things, but that doesn't mean you can't do them anyways. Ethernet cables are tiny, the hole required to pass one through a wall is trivial to patch over. If you have attic or basement access as I did in my last apartment, you can often follow existing cable or telephone lines from there in to the wall, then just swap the faceplate from the single outlet to a dual combo or a keystone-style configuration. In that last place the laundry room had a vent pipe going straight to the attic. I used that to get wires upstairs for the bedrooms by just climbing up there and dropping some plenum-rated wire down the tube. The other ends followed a cable wire down in to one of the bedrooms and was just punched through the wall behind the box to reach the other room.
Tucking wires along baseboards, running them under carpet, through ducts, etc. All great ways to run low-voltage wire in a residence when you can't just do it the right way. I'd never recommend a business network be done this way nor anything carrying dangerous power levels, but for home ethernet it's perfectly safe and much better than any wireless ever will be.