I was thinking this further through. What you write was indeed the next thought… and the reason we don’t grow in multistory factories is… cost! So sunlight is the OG for greenhouse growing. Cost of m2 free ground or glass do not matter when compared to building space, lights and energy.

This does lead me back to the idea that to cover greenhouses with translucent panels, you would need translucent panels to have undergone a price drop comparable only with regular panels. Which is unlikely. And then you have risks like hail risks that multiply when covering greenhouses with panels. Although that might be an upside, since greenhouses in NL are actively going towards break free glass which is pretty expensive. So perhaps there is a break free translucent solar panel upgrade route that could work out. (I am sceptical, but it is a nice idea indeed. Light is a spectrum and not all light is equal in photosyntesis.)