Comment by gmueckl
I think this is because of how extremely cleverly they picked the art style for the game. You have a lot of diffuse surfaces for which prebaking the lighting just works. Overcast skies allow for diffuse ambient lighting rather than very directional lights, which force angle-dependent shading and sharp high contrast shadow outlines. And the overwhelming majority of glossy surfaces are not too shiny which also helps out a lot. All of these are believable choices in this run-down, occupied, extremely dystopian world. And the texturing with its muted color palette pulls it all together.
There's been a rumor going around that developers move away from prebaked lighting primarily because it complicates their workflow.