I was going there next; you beat me to it.
When Facebook, Google, and Twitter announced they were going to do ad transparency databases, they said you're going to see all the ads that are run during a political cycle and you're going to have data about every single one of them: who bought the ad, how much they spent, and some information about targeting, although they've reneged a little on that. It was all going to be searchable and there was going to be API access so that researchers and journalists could literally download the entire data set and study it themselves.
That last piece has not been done. The searchability and the research capability of that data set are not up to the standard we need. I don't believe the companies are going to get there on their own, nor should we expect them to. These are businesses. They don't want to reduce the amount of commercial advertising revenue coming in the front door. Their responsibility isn't to protect the public interest. That's ours.
If we want that standard to be in the market, we're going to have to put it in the law.