This bit:
> but until path tracing times are measured in minutes per frame, as opposed to the hours or days they are now, ray tracing (or rasterization, especially micropolygon rasterizers like the one powering RenderMan) remains the better option for many classes of rendering tasks.
wasn't even true in 2016 - RenderMan (PRMan) 19 added a pathtracer and eventually in 21 removed entirely its REYES rasteriser, and pretty much the entire VFX film/animation industry is using pathtracing now.
Artist time is much more expensive than machine time, and not having to tweak things like materials / lights in the PBR realm that path tracing lives in per shot / sequence to fake things like GI (like the article mentions is a good alternative - it's not) is where a lot of the speedup has come from with iteration times.
If anyone's interested in state-of-the-art for film VFX, five papers on the five most used pathtracing renderers used in VFX were recently released:
https://jo.dreggn.org/home/2018_manuka.pdf
https://www.yiningkarlli.com/projects/hyperiondesign.html
https://www.arnoldrenderer.com/research/Arnold_TOG2018.pdf
https://graphics.pixar.com/library/RendermanTog2018/paper.pd...
https://fpsunflower.github.io/ckulla/data/2018_tog_spi_arnol...