Can it? Yes. Will it? Only if the NX is a truly massive failure.
Let's say the Xbox One ends up this generation somewhere around 40-50m. The Wii U will be around 14m. That's already 54-64m; making the PS4 need to reach 108-128m to keep its 50% marketshare.
Now, let's say the NX turns out to be a bigger flop than the GameCube and sells only 20m. That would represent a toal of 74-84m; making the PS4 need to reach 148-168m.
You see, even if the NX flops, it will be very hard... unless you think the PS4 will surely outsell the PS2.
Bet with Teeqoz for 2 weeks of avatar and sig control that Super Mario Odyssey would ship more than 7m on its first 2 months. The game shipped 9.07m, so I won