Once gpu hardware becomes good enough that even low end computers can support real time ray tracing at usable speeds, game developers will be able to remove the lightmaps, ao maps, etc that usually comprise a very significant fraction of a game's total file size. The problem with lightmaps is that even re-used textures still need to use different lightmaps, and you also need an additional 3d grid of baked light probes to light dynamic objects in the scene.

Activision has a very interesting lighting technique that allows some fairly good fidelity from slightly lower resolution lightmaps (allowing normal maps and some degree of specular to work over a single lightmap texel) in combination with surface probes and volume probes, but it's still a fairly significant amount of space. It also requires nine different channels afaik instead of the three that a normal lightmap would have. (https://advances.realtimerendering.com/s2024/content/Roughton/SIGGRAPH%20Advances%202024%20-%20Hemispheres%20Presentation%20Notes.pdf)