"the incentives for any individual reporter are just too great - having the government make a major policy change based on your article is basically the brass ring for an investigative reporter"

Yep, this is the framing I came here looking for.

Investigative journalists live in the same asymmetrically-incentivized world as social science researchers. If the reporter had looked into the phenomenon and concluded "yeah, boring technical logic pretty much works as expected here" then there's no story.