What 'GAME' developers? Perhaps they were just debasing that on a bunch of marketing terms because they have 2GB extra unified memory, while they're basically the same architecture and performance? Most game devs tend to push the limitations of PC and console hardware, and that includes overdoing it past their limitations. The end result ends the same for all platforms: optimization.
Did SONY say that their console is "50% more powerful" than the Xbox One? Did these 'game developers' tried to develop on the Xbox One or were they EXCLUSIVE to PS4? Details, man, I don't even know if you can cite your sources.