I don't think PS5's target resolution is going to be 4K and the same will probably apply to Microsoft too. It's probably going to be either 1080p again or 1440p. AAA developers are obsessed with trying to immerse the gamers and graphics is a big part of that so they'll be investing a lot of time on light transport simulation ...
Of all the console manufacturers that has the highest potential to target 4K I think it's Nintendo since they don't really care enough about matching industry technical standards. While they'll be adopting physically based shading like this generation the new HD twins are going to roll around with monte carlo based global illumination ...







