The PS4 is nearly at 100 million. And it is over 5 years old. At some point, it has to slow down. Here are the options:
If the PS4 gets a hefty cut during holidays, it can still sell, but I would like to see the corporate projections first before picking a winner.
If the PS5 is announced to be launching sooner than we realize, then it should soften PS4 sales.
If the PS5 is coming and the rumored Portable version is announced as well as the console version, then Nintendo needs to watch out.
I know all this. Thing is just, if the Switch is very far in front while dillydallying then the prospects of those who said that the PS4 will keep up with Switch sales until the holidays season looks rather grim.
I'm actually more waiting for February NPD since the January Switch numbers are getting skewed a bit from the Smash Ultimate boost, but by February this should have normalized. The other question that month is how much, if at all, multiplats like Apex and Anthem can boost the aging consoles that month
The Nintendo eShop rating Thread: http://gamrconnect.vgchartz.com/thread.php?id=237454