In the coming 2-5 years most 3D games will be ray-tracing-based and streaming technology would not only be very suitable for it but very beneficial, allowing huge game worlds with unlimited detail. Highly detailed or scanned 3D objects take easily terabytes of storage and streaming everything from the servers is really the only viable option.
There's local cache(s) too to help with latency. Basically, you have to keep your GPU memory full, cache on RAM, cache on SSD, cache on HDD and continue all the way down to the cloud servers. Check out this demo for example, which streams data from disk http://www.youtube.com/watch?v=HScYuRhgEJw
Game devs are not interested in making games that no one will be able to run. Regardless of the benefits of raytracing it is currently inefficient when compared with raster tech currently on GPUs. Hardware tessellation makes inefficient voxel tech moot except for scientific purposes. We can already stream data from the hard disk to the system ram into GPU memory.
I'd put mainstream voxel/raytracing tech as more like 10 - 20 years in the future.
