I disagree that many developers have targetted the Pro - its that games haven't stood still or been limited by base consoles. That is different. Sony Devs though can manipulate their game to hit certain parameters on base consoles where as multi-platform Devs build their game and then try to get it running as it is on the older hardware.

What I mean by that is that if an area is to complex or has problems running at say 1080p/30fps, they can change that area in the game. If its the view, the amount of objects in the distance affecting performance, a Sony developer can change the amount of objects, can even put some object like a wall for example so the load on the GPU is reduced. In a multi-platform game, that 'view' cannot be blocked off because that would change the game from other versions. It makes more sense to reduce the resolution - either dynamically for that specific area or permanently so that the versions remain the same.

Its the fact that all versions - inc those on Base XB1 - have the same geometry, views etc that means all these games run differently because of the different hardware. Its not like they change the game to run on XB1 with its weaker GPU, they reduce the resolution to run the game.

Its no different from games like Uncharted 4/Lost Legacy, Horizon: Zero Dawn, God of War etc. If areas struggle to run at a full HD, they can change that particular area in the game to reduce the load on the GPU to hit their target. As the game only releases on Playstation, it enables the devs to adapt the game to the hardware rather than try and get the game as is to run at acceptable levels. You can change the game at its core design to reduce GPU load rather than change the resolution for example to reduce the load.

Its the same principal with Xbox Exclusives too - games like Gears 5 and Forza Horizon run at 1080/30 and Forza Motorsport runs at 1080/60 but as we know, multi-platform games struggle to hit full HD. Even games that perhaps don't look as impressive, or at least on a par with these. Its because Xbox devs can change things in the game to reduce the Load on the system where as multi-platform devs make the game and then try to get it running. They can't go changing the game too much otherwise its not quite the same game.

That's the advantage for developers who make a game for a single platform and why single platform games tend to run better even if the look as good or better than anything out there.