Really, apart from quoting a page from a article that says very little, what evidence do you have for that ?
I was peripherally involved in a feasibility study to track things in a very large building, this might be a good introduction:
Location Tracking Approaches
As of c. 18months ago the base kit to do this (and the 'management system' sold by the likes of Cisco) ran to, well, lots of money.
Havn't looked into it recently, but WiFi routers already have RF beam forming (so there's a vector) and with some time-of-flight capability for distance... well, once this gets down to even twice the price of a standard WiFi access point then tracking everyone by their phone within buildings will be commonplace.
Marketing types love this sort of thing: Our new expensive widget sales point - how long did people look at it? did the same people come back? Where else in the store did they go? What did they end up buying? What credit card did they use? Are they already in our database? etc. etc. etc.