Also, i'm hoping my future glasses have some kind of mechanism built in that will let me text with my mind... even if that means thinking about moving shapes or colors or something to do it.
http://techcrunch.com/2015/06/02/6-1b-smartphone-users-globa...
http://www.businessinsider.com/smartphone-sales-forecast-201...
The thing is a) those are all a few years out, b) they're interconnected. VR will happen first because it's got an obvious path to a large consumer base. That will lay groundwork for AR, which is probably the actual Next Big Thing. Wearables/IoT/3D printing are really an extension of the miniaturization/customization of longstanding technologies, but are all experiencing severe growing pains (wearables : size/batteries, IoT : cost, 3D Printing : materials).
As for the rest: wearables hadn't had a really strong use case - so it's either a niche or a fashion/status object - and maybe that's what will limit growth even when size/batteries gets solved ?
IOT: cost is definitely a huge barrier, but will it be that huge deal ? or just another feature in the stuff we already buy - sold to us through the same big companies, with a few specialized products ?
And 3D printing - don't you think a 1-day Amazon 3 printing with the most optimal processes will win, for most consumers ?
As for 3D printing, the biggest problem in my opinion is modeling, not printing itself. The cost of stereolithography printers is finally dropping, and extrusion printers are getting easier to use, but actually printing things is useless unless you have a model you can print. Most people just don't want to spend the time or effort to create a model, especially when you can walk into a store and get a higher quality item that's professionally designed and manufactured for dirt cheap.
I want to bet on sunglass sized AR, but it seems like we'll need some material science revolutions to shrink down the requisite hardware to have the kind of useful experience is imagine
A long way to go, but we'll be there eventually :)