looking forward maybe five to six years, i think we'll see sony definitely showcasing a ps5 (either for release in 2019 or 2020), with a big maybe on microsoft actually pursuing another investment of billions after two decades of pretty much nothing but losses for the division. if anything happens to xbox, i expect it to be a digital platform or at least a digital box, sort of like what they were going to do with xbox one but more fully realized.
nintendo will be effectively making nintendo boxes - toys that feature some sort of quirky element to enhance their games and perhaps only a few others (if disney, lego, and other family-friendly game makers are doing that for dedicated hardware six years from now). this will reflect a growing trend among other publishers in having a platform to themselves, except one that's digital. it may be still part of the console for playstation, but also offered elsewhere, a prelude to a new wild west of sorts resembling the late 70s and early 80s where big publishers become their own platform providers. steam will have had a 15 year head start. i don't know what could impede its growth.
on the mobile side, i don't think phones will become more complicated, but the games will be, and the people who started playing games on mobile will be adapting to such experiences, sort of a parallel to the 70s-80s-90s progression for the traditional market.
but right now i think we're seeing the beginning of the end for the traditional market.