Re: Communication, Communication, Communication
I'm not sure Wifi at work is commonplace, even in offices, plus people may prefer to use their own mobile for privacy reasons (the same way that some people will now check Facebook on their phone at work, even though they could just use the work Internet-connected PC).
Malls/bars/restaurants - a large number of these are those annoying ones you have to sign up and log in. It's easier to use my mobile data. Plus the faff of finding it out - if I'm in a shopping centre and want to send a text or look something up on the Internet, I don't want to have to faff finding out whether there is free "Mall Wifi", and if I can find its password. That's assuming I'm in a "mall", most shops in the UK aren't. Then it's not uncommon that Wifi connection is poor quality, and I'm better off staying with mobile.
I have BT hotspots included in my contract, though the rare times I remember to look for it, there are none nearby. Plus you're contradicting yourself here - you're arguing that Telcos have nothing to sell anymore, because people can instead use a service sold by the Telco?
I'm still going to want mobile data in order to cover all the places where Wifi isn't available, which for me is most places outside of home, and since I've got mobile data, it's usually easier to keep using that rather than faff with seeing if I can find Wifi at any random point.