I did :). No point doing safe predictions. So do you think it will be before 2019?
Highly unlikely as the xbox strategy is now somewhat different to the 360 days. As you say and I do agree the focus will move to an xbox branded pc strategy for other hardware makers to enter the the xbox live market with gaming pc hardware. However much the same as the Surface strategy, Microsoft will want to keep one foot into the hardware space, - not to profit from it, but rather to showcase what it can produce for inspiring manufacturers with cutting edge design, power and form (in fact with windows phone excepted, MS has never before been so involved with hardware like now with 3 types of surface iterations including laptop and 2 very different versions of xbox on the market). I believe the XboxOne X is the beginning of this strategy moving forward.. It basically is just a powerful pc. MS even said themselves that it never expected the One X to be a huge sales driver, and yet it even surpassed their expectations. Again they are not in the hardware space to make money, - its the xbox live subs and service where the money is being made and that remains very profitable.
The near to mediam future for the xbox brand will be a hybrid pc/console approach with the console effort just being a token presence like surface. Much different to the old 360 days but nevertheless its consoles (or pc in a box) not going away anytime soon. Especially by 2019, that verges on a silly prediction imo. MS has for years been saying they are committed to xbox and people on this site for years have been making the same console exiting prediction which time and time again never ever even eventuates (it must get disappointing for them lol :))...Furthermore I believe the profitability with xbox is better now than it was with the 360. They have more reason to stay on, with less focus on hardware and just the tokenistic (showcasing) presence that I explain above.;- Until of course Xbox/ PlayStation just become a service and completely replace consoles altogether. Analyst Michael Pachter is very firm in his belief that this will occur by the 2020's. By then this is where MS will have a better preparedness for gaming. every pc, tablet possibly phone will become your playstation and xbox. And the likes of Sony and MS can still make variants for showcasing design and potential. This is the ultimate future.
Xbox 360 and Xbox One