Apparently, it's already the case in some games :
"Another important part is reflections, and although we do have real-time raytraced reflections since Killzone Shadow Fall, cubemaps remain a very important part of the pipeline."
https://80.lv/articles/horizon-zero-dawn-interview-with-the-team/
But i agree with this point.
I see developers using this tech only if it's a real differentiator. As long as they could put ressources elsewhere to get a better overall result, they won't use it.
Also :
"The reason we chose to once again use a prebaked solution instead of a fully real-time solution is simple: the quality is higher, and the memory cost and runtime performance cost is really low compared to a fully real-time solution. We have the opportunity to stack multiple irradiance volumes as well, giving us higher fidelity and resolution.
Another reason for us not to use a fully real-time solution is so we can add a lot of non-runtime lights into the equation in order to really paint with light, and create a more balanced, stage-lit experience. These ‘bake-only’ lights get baked down completely (primary and secondary rays) and provide a more rich-looking lighting scheme with a lot of gradients in both color and intensity. This enables us to create a slightly more unique version of reality and makes our games stand out a little bit. We can also flag lights to be sun bounce lights, which means we can render them into the sun bounce passes and thus have them affected by time of day scaling and recoloring."