It's not diverging in that people now have more devices to accomplish a task, but rather converging in that each of these devices are slowly evolving towards the same end (or maybe towards 'each other').
Phones started as phones. Then they could text (aka instant message). Then they could browse the net (aka surf). And are now evolving to be able to accomplish gaming and varying levels of productivity and content creation all in one.
Tablets started as "computers you could write on" and are now expanding as a gaming, productivity and communication mediums.
Desktop computers (and more specific to this idea, laptops) are the baseline for performance and capability really, but are expanding their usage model with touch interfaces, improved portability, and smaller and more attractive chassis.
They're all slowly starting to overlap and accomplish the same tasks. Currently, a venn diagram of computing of cameras/phones/laptops/tablets/desktops/consoles would probably look like a jumbled set of olympic rings; in the future, I think it'll progress to be more like this.
I don't think we're near the point of a 'super device' just yet and I don't think it will bring obsolescence to any one type of "niche" product; I think there will always be a [smaller] place for Game Boys, DSLRs, dedicated GPS units, desktop computers and other 'specialized' devices. But I think it's quite conceivable that twenty years down the road we may all have a phone/tablet/laptop hybrid to carry around that simply docks with keyboards/TVs/controller accessories/etc as a mainstream computing device.
THese devices are nothing but a distraction to real life.
Outside of a phone for emergency, these things are great when you travel or toilet material. If you use any of these devices more than 1 hour a day, chances are....you probably need to get out more and live some life.
