No way PS4 can keep growing with heavy competitions this year.
I think 2016 is the plateau.
Nope its actually possible that 2017 could be the PS4's peak year.
-Sony has exclusives like Horizon that has potential to be a big hit, Uncharted the Lost Legacy, GT Sport (the first GT game on PS4 and will do gangbusters in Europe) and other 3rd party exclusives that add up to more sales.
-PlayStation also has marketing deals in place for most of the high profile 3rd party games such as Red Dead Redemption 2(the single biggest game releasing this year), Destiny 2, EA's Star Wars Battlefront 2, and the next COD just to name a few.
-This isn't even taking into account other unannounced games or titles that can possibly release this year still like FF7 Remake Part 1, and Dragon Quest 11(which will dominate in Japan though not as much as the 3DS/Switch version)
-Finally Sony will likely drop the price of the PS4 to $199 and the Pro to $299 next holiday.