When will ray-tracing replace rasterization?

Ray-tracing produces images of stunning quality but is difficult to make interactive. Rasterization is fast but making realistic images with it requires splicing many different algorithms together. Both GPU and CPU hardware grow faster each year. Increased GPU performance facilitates new techniques for interactive realism, including high polygon counts, multipass rendering, and texture-intensive techniques such as bumpmapping and shadows. On the other hand, increased CPU performance and dedicated ray-tracing hardware push the potential framerate of ray-tracing ever higher.