Define "fine". The OG PS4 has to render some PSVR games at 720p and under resolutions sometimes in order to keep acceptable frame rate, like in the case of RE7. The OG Xbox One frequently runs non-VR games under OG PS4 resolution and even under 720p, so you really think that OG Xbox One would be able to give a satisfactory experience in VR?
what modern games is the one running at under 720p ? Regardless if people are fine with psvr at 720p I don't see why they wouldn't be fine with xbox one games at 720p. The ps4 also has horrible tracking that MS shouldn't have if they use their slam tech in their mixed headsets