It's a funny old thing, the 'death' of the 26" wheel. There are almost no new bikes being made in that flavour, and no new forks (although you could just use a 650b fork and live with the extra clearance). Wheels and tyres are still around, so there will probably always be bikes with 26" wheels going around.
I still think the jump to 650b from 26" wasn't all that worthwhile, but now that it's happened, there is no point in both those sizes coexisting, because they're not that different. What I am quite excited about, is 29ers, and how much better they've gotten for all purposes. When they first came out they were spindly wagon wheels that handled like cruise ships, and now amazing enduro bikes and DH bikes have harnessed 29" wheels successfully, thanks to boost spacing and truly modern geometry. I've gone from being a skeptic to a convert when the time comes to replace my 2009 Orange Five. I think the newer generations of 29er will spell the end for 26 AND 650b, for all but the shortest riders, and even those might struggle to find a 650b that's small enough for them.