GTA 5 was developed with Next Gen consoles in mind.

It's obvious that V was developed with the next-gen consoles in mind for a long time. The build logs suggest that the PC version has been in the works since at least early-to-middle 2012, and 'Orbis' is mentioned in the game files, which happens to be the OS of the PlayStation 4.

I'd imagine that when developers are done with the raw assets of their project, they start to work on the platforms their game is supposed to release for. In which case the aforementioned assets are downscaled to a quality each given platform is capable of. Since PC happens to be the platform with the most power, games also have higher resolution textures, higher poly models and higher quality audio files [and probably cut-scenes] on it compared to their console counterparts

PS4 and Xbox One's architectures are basically the same as the PC, so porting games from the latter is fairly easy. The only major difference between those platforms is the way the system and video RAM are utilized, the different Operating Systems and the different APIs. But other than that, it is easy to work with them and it's easy to port assets between each of them.

Personally, I found a next-gen release rather unlikely about a year ago or two. However, given the huge success of the PS4 and Xbone it was kind of obvious that Rockstar wouldn't want to miss out the opportunity and release GTAV for those platforms. Who knows, maybe Microsoft and Sony had expected their new consoles to be as successful as they turned out to be, which would explain why R* started to work on the PS4 version over a year ago. Or maybe they knew that a next-gen release would be profitable either way, since it is GTA. Just take a look at GTA IV, the game was released in 2008 when about four to five times less PS360's were on the market compared to now, and it sold in six years almost as much as San Andreas did in ten years, which, in turn, was released at the end of the console generation.

The series is becoming more popular with each new release, and they made so much money with V on the PS3 and Xbox 360 that there is practically nothing that could hurt them financially, at this point.

Credit to: Andreas (GTAFORUMS)

Andreas