First, those render times sound hugely inflated to me.

Second, this is apple and oranges. Just look at 'ray tracing' is simple and naive. Pixar uses their own renderer, PRman, which has been developed over multiple decades. There is a big difference in renders for film, including micropolygons, texture filtering, more textures, higher res textures, way fewer lighting cheats, much more customization, motion blur, depth of field, sub surface scattering, multi-layered glossy surfaces that are neither fully specular or diffuse, better area lighting models, etc.