It might be a none issue if Sony were competing with MS but they're not now and have stated as much. They're now in competition with the PS2 and they'll do everything in their power to make sure people opt for a PS4. If there's a month when the XB1 has a big game and the PS4 doesn't, it makes sense to make sure PS4 owners have something to play and the media have something to talk about. Regardless though, PSVR has given Sony an opportunity to bolster their portfolio of games for the vanilla PS4. The fact No Man's Sjy is likely going to get a VR version in no way will impact the vanilla PS4 version. The only likely outcome is that those with No Man's Sky already might decide to buy the PSVR later on when they can afford it.
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.