It’s cooperate or die. The easy sources are mostly gone... mid level political people and normal workers can be hunted down pretty easily with modern tech, and subject to criminal sanction in some cases.

A close relative was a well known local public official in the 80s and 90s. In those days, the investigative reporters made more than he did and were relentless. In one case, he caught a guy climbing into the plenum over a ceiling tile to try to hear portions of a meeting in executive session.

Now, good reporters aspire to work in PR shops.