That's my thoughts as well.
Surely the engineers (software and other kinds) and the content creators will still need powerful general purpose computers to enable them to do their work effectively. These really can't ever go away, at least for the foreseeable future (~50 yrs). Oh it might change somewhat, but for the most part there isn't any reason to change from a general purpose computer. So there will always be some market for those types of computers. Not to mention the scientific community needs (and other big data computing). These type of computers may turn into a somewhat limited market, but the need will always be there.
Speaking from experience, since I make my living from computers, having a general purpose computer at home allows me to do interesting hobbies (not just gaming) as well as the occasional work-from-home support type issue. Speaking from an education point of view, general purpose computers are their own best teacher as you get instant feedback to what works or not. If all that is in the house is tablets or smart consumer oriented devices, those are not meant for learning the nuts and bolts of how things computer things work. I fear for future generations of kids if that is the case.
A consumer use device is another story entirely, and what I think the big players are positioning themselves for now. Will tablets and smartphones become so ubiquitous that nearly all households will have 1 or more of these types of devices? That is more likely in the near short term (~10 yrs). Who knows what the next big thing will be in terms of a new paradigm of consumer usage? It might be this VR thing people are all excited about these days. Taken to the logical next step, there will be more and more specialized computer like devices that offer accepted forms of usage. Those types of devices will be likely be low power, ripe for market exploitation as the article eludes to.