First off, many genres of games don't need dynamic global illumination, so that is less of an issue that you make it. In fact, the only games I've played lately that have a global illumination model were Guild Wars 2, the Sims 4 (and yeah, 3 is generally better, but it isn't terrible) and Tomb Raider (2013 version). I have dozens of strategy, adventure, RTS, and racing games that have no global illumination at all. I don't play a lot of shooters outside of the few I know don't make me sick, but yeah that market uses a lot of global illumination.
Second ray casting and ray tracing both can support forms of dynamic lighting, assuming that's what they're using, and I seriously doubt they are doing something else like marching cubes to extract polygons, The problem id had with it in RAGE (which was also voxel based) was the GPU just couldn't keep up for lights and shadows, so they didn't put it in (and are working with hardware manufacturers to make next-gen cards more voxel light/shadow friendly). Techniques like real time radiosity tend to leave blocky shadows due to needing unacceptably large patch sizes. Real time photon mapping (a faster technique than radiosity) tends to create "grainy" images. AFAIK, there really isn't an acceptable solution yet.
In college I wrote a radiosity renderer that was certainly not realtime on a 100Mhz processor with some dedicated graphics hardware (an SGI Onyx, I believe), but it rendered scenes with eye catching detail, including dust particles in the air, which is really difficult to simulate with polygon renderers, or at least was last time I tried (but rendering took something like 72 hours... sigh).
Where polygon rendering tends to look fake to me in that architecture video is with curved metal objects. Something doesn't quite look right, especially with the sinks, but maybe it's because reflections are missing. Some polygon based graphics actually run something akin to mini raytracers in a hardware shader to get reflective curved surfaces (in fact, I've written one for shadows and I could do curved surface reflections with it).