Is Z-Wave on the way out?
Not with Zwave 700 coming on board, it isn't... Unless they come out with Zigbee 2.0 that somehow magically lowers power usage.
Amazon buys ST?
Not too surprising--the Echo Plus and Echo Show v2 both have built-in ZigBee hubs, and it seems most manufacturers of commercial ZigBee hubs want in on the Alliance. They are definitely a big player in the field in terms of size, money, and possibly therefore power; hopefully they use it for good. 
I see they are at the "Promoter" level in the Alliance, the highest of the three membership types, joining the ranks of SmartThings, Signify (Philips Hue), Comcast (probably for Xfinity, famous around here for keypads), and others--one of about 16 "board"-level members.
But there's already a ZigBee 3.0! (Not sure that there are any changes regarding power consumption, but unlike Z-Wave, there isn't just one manufacturer of a proprietary chip. Notably for end users, they did merge the ZHA and ZLL profiles, among others, into one, in addition to some security and other changes.)
Woah, could this mean the end of the "faulty bulb" era?
It should...
