Some combination of wearables, AR/VR, IoT, and consumer 3D printing.
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 ?
I'm with you on wearables - I've been trying to think of mass-market use cases for at least a year now, but I just can't find anything that's appealing outside of niche markets like disabilities and medical monitoring.
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.
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).