Local newspapers need ad revenue; down-ballot progressive campaigns need a way to reach niche audiences in a small area. Moreover, progressive campaigns benefit in the long run from a vibrant local news industry. However, it is difficult to execute an ad strategy across a wide variety of local newspapers - there’s too much paperwork involved.
Ysiad Ferreiras describes an experiment he ran to create an online marketplace which would address this challenge in his Great Battlefield interview, at 31:35. This effort failed, mainly due to poor timing caused by the pandemic. It’s reasonable to imagine that a second attempt at this idea might work.