I believe that the initial idea there was to refer to notable landmarks and these company signs are readable from a distance.

But yes, they could serve well as ad space.

This also works much better in the vast slabs of the world where roads don't have names, or if they do, they're signposted badly if at all. (India, Japan, most of Africa, etc.)

So you think they weren’t getting paid for this? You think they just freely mention corporate food companies purely for users benefit?