Facebook to block data broker insights from its ad network

This is a pretty big deal, right? Facebook's data has to be some of the most valuable and personal data ever gathered. It seems like a real win in terms of privacy, one that would have some impact on FB's bottom line assuming they sell the data at a good price.

OTOH, it does nothing to alleviate the overarching concern people have for FB's growing access and power over all of its users, as it continues to collect their everyday personal data. The danger of abuse is not significantly less just because the data is exclusively used by Facebook.

Aren't all data brokers basically all like Cambridge Analytica? Aside from the electoral influence thing. But do we even know data from data brokers wasn't used in similar fashion? Seems like a small chance that wouldn't happen.