I'm unsure, but my gut tells me there's regulations/building codes that require landline cabling in (new) residential homes, and of course, not data cabling. Like I said, it's just a hunch, though.
Data cabling is omitted from new builds because it doesn't sell homes and is just a cost.
The only recent comparison I can think of is how some cities actually required lead pipes for drinking water for decades.
I don't think so. I think he's suggesting that without a code that does require it nobody is going to bother including it even though they really should.
Very very few people had interest in the slight added expense of the cable and labor to do as such -- all insisting that they only needed it to / from cable modem area to their aspirational wifi router location.
This is like turning down indoor plumbing and instead putting a nice heated, carpeted breezeway out to an outhouse you rent.