I guess the idea is that if your mobile device is powerful enough, then you're already leveraging a hybrid device. If you look at something like the iPad Pro, we're well along there already in terms of processing power (even more so CPU wise), all you're missing is a big screen TV output, and some bluetooth controller support. A video game console itself doesn't need to exist in the format it does now, and it's not hard to believe that eventually a mobile phone could replace a majority of our computing needs (except those that require intense power).
But the simple way to get around that is with server power, much like we we do with Hadoop and clustered processing of large data sets. Nvidia offers game streaming already, streaming to... Nvidia shield. So really your mobile device only needs to be good enough to provide lagless off shore processing to be comparable to any console today, and any console in the future.
That future isn't too far away, and I have no doubt MS sees that as a possible path for their future. I've seen W10 continuum in person, I've seen their mobile phone convert to desktop and begin plugging away on MS Office. So it's not too absurd when your outlook is 10-15 years or so. 10 years is a long time, because our rate of technology improvement appears to be somewhat exponential. VR is already on mobile, much earlier than expected. What if VR does indeed become the future? Do we really need realistic graphics, or do we just need high frame rate and resolution.
Anyway, just my thoughts on the subject as a whole.