The hype was that you could take a huge pile of data and turn it into hugely valuable insights.
The realization is that any random pile of data likely doesn't have anything in it that is worth paying for:
Here's our analysis!
We already do/knew that.
Some people have really good, valuable data sets. Most people don't.
It’s an epistemology / ontology question, as folks familiar with the humanities would spot in little time. Aka it’s not “data” until something empowers the created metric a meaning.
I think the point is that "data" is useless until it becomes "knowledge," and that turning data into knowledge is a complicated and philosophical act. Business being business, most of the people running the show were never interested in the deeper questions of how to create knowledge. They just wanted a new arrow in the quiver. Once they realized the cost of actually doing the work, it became much less appealing.
The realization is that any random pile of data likely doesn't have anything in it that is worth paying for: Here's our analysis! We already do/knew that.
Some people have really good, valuable data sets. Most people don't.