Wouldn't that make every ad funded newspaper and TV channel a paid mouthpiece of its advertisers?
Advertisers are almost completely in charge of what shows makes it to TV - that's what they do at https://en.wikipedia.org/wiki/Upfronts - they show advertisers proposed shows and the ad execs pick which ones make it to market.
The advertisers can't pick the specific content of news type shows, but they can pick which news shows are broadcast in the first place.
To have anything resembling a similar amount of say about how a privately funded media company operates, I have to boycott all of its advertisers, which likely entails long-term lifestyle changes.