Meh, real-time reflectance functions are still going to be all sorts of approximations. To say nothing about stuff like real global illumination. And SDFs are really nifty but a function that represents a complex, detailed, non-stylized/cartoony scene such as those in modern games is not going to be fast to evaluate.
Not to mention other aspects of the overall visual experience, eg, everything about scene dynamics, object interactions, etc. A bigger compute budget is always welcome.