You seriously think Sony cares about competing with the PS2? They only care about keeping the PS brand profitable. If it keeps up ahead of PS2 then great. If it doesn't then who cares? They sure don't.
If X1 gets a big game in one month with nothing major for PS4, what does that really mean? By 2017, not much, especially in the light of Bend's horror game, SP's new open world title, GT7, GoW4, FF7R and whatever other JPN exclusive is coming.
NMS's is just an outlier example as it is a regular release ever since announcement. If it gets VR support then that is obviously good but it has never been designed like that. The reality is that most ppl are not going to play NMS as a vr title (if it is one) because most ppl are not going to care about forking out a few hundred more for a VR set when they do not need it. Experience alone is not going to offset the price point of VR. There are going to need to be meaningful software that actually requires the use of the device.
As as I mentioned before, VR games becoming non-VR is not going to create a surge in hardware sales at any point of the year unless it is some big brand IP like GT7, nor will it look like anything against a major X1 release. The only ppl who care about this latter issue are forum users, which unfortunantely make up a minority of the ppl actually buying game harware in the first place.
There is no reason for Sony to play a numbers game in terms of software when they have more important things to do: make VR successful. If that happens, they will move hardware.
Are you under the impression that I'm one of those silly little teenagers who can't bare to think the PS4 might lose a month? I'm just offering one possible reason Sony might just do what I've said. Just the fact they can make sure there is a constant stream of games would be enough. Now Sony are benchmarking against the PS2 they'll want to make sure there are no lulls, whether it's because of a lack of software (in a paticular month) or XB1 that takes sales away from the PS4. Even possibly the NX if it releases.
The PS5 Exists.