I expect the next wave of GPU hardware will address some of the current challenges, with more RAM and shared memory, like Nvidia´s NVLink, available in cheaper VGAs.
I come from a Machine Learning background and I can envision a neural network for the creation of a 3D scene from beginning to end. It will be able to test different settings, choose what 3D assets to use, and try varied materials. With enough training, the network will be able to tell good decisions from bad and will become more capable over time. Render engines are almost real-time, and settings are simpler than ever, so the creation of a neural network is no longer in the realms of sci-fi, and simply a matter of time.