[jefftk]

Depends on the advertiser! Big brand who mostly wants to reach everyone in a geographic area? Targeting doesn't matter. Retailer that wants to bring someone back in to complete a purchase? Without targeting they won't buy ads at all.

(Disclosure: I work on ads at Google)

[dannyw]

You suggest this as if the majority of ad spending comes from small businesses trying to retarget their customers; when the vast, vast majority of ad spending comes from big brands; and your mom and pop business isn't running a sophisticated ad targeting campaign.

Adtech is for the establishment.