This may very well be the case if you consider that:
1. The PS4 is technically superior to the Xbox One in terms of processing power. We've seen this in various games already where the PS4 version trumps the Xbox One. Even with the newly added 10% processing power increase the Xbox One received (due to Kinect going bye bye), I doubt it will keep up with the PS4. Somehow the latter just seems miles ahead in terms of optimization.
2. Judging by GTA 4 on PC, it seems that Rockstar has massive issues in porting games over to the PC whilst keeping them playable on anything less than a cray super computer. If that happens with GTA 5, then yes, the PS4 might very well be the "better" platform to play it on. Give it 3-4 years and about 100GB of patches, the PC might have a chance to catch up.
Time will tell. That's one of the best things about owning both consoles and a PC. But with the price of these things lately, I don't know many people who can afford that luxury.