Silverforce11
Lifer
Sure you can. nVidia is giving access to the source to the developers and working closely with them.
But even then having access to source code doesnt mean that the developer cares about other companies. Dice is a good example as a console developer they dont bother with optimiziting for nVidia's hardware.
What exactly are you smoking? Every single DICE game in it's history has ran excellent on NV hardware.
A 780Ti is very competitive vs R290X and even 980.
Go look back at BF3, BF4, Hardline, DAI (AMD sponsored, ran excellent on all hardware).
Battlefront just repeats it. Even a 960 is putting out amazing performance at 1080p high/ultra settings.
Regarding GW source code, devs can pay to get access. They can also pay extra to modify it, but with the clause that it must not reduce performance on NV.