Many publishers are typical corporations, with a large number of shareholders, none of which get to even talk to the journalists.
Even among those owned by individual billionaires, the evidence is lacking. The Washington Post, for example, has broken quite a few (often negative) stories about Amazon. The Seattle Times recently broke much of the 737-MAX scandal, even though they are faily dependent on Boeing. The New York Times doesn't even write much about Mexico, let alone topics related to Carlos Slim's financial interests.
The motivation to own these reputable papers seems to be far easier to explain as a status thing. Kinda like NFL teams, but for the more intellectual billionaires.
http://theconversation.com/the-manipulation-of-the-american-...
https://books.google.com/books?id=3De8nd_B_C8C&printsec=fron...
The first episode deals exclusively with Bernays, and the following three episodes follow a political narrative of impact.
I believe Curtis’s “Hypernormalisation” would be more salient to the narrative here, which discusses the funding of misinformation as an alternative to traditional authoritarian power structures like censorship: https://youtu.be/fh2cDKyFdyU
https://slatestarcodex.com/2019/09/18/too-much-dark-money-in...
Alexander Hamilton didn't create the New York Post to make money. Henry Jarvis Raymond (politician) and George Jones (banker) didn't create the NYTimes to make money. Stilson Hutchins (politician) didn't create the WashingtonPost to make money. These newspapers were created to further their founders' political interests.
And in case you were wondering, Bezos didn't buy WashingtonPost to make money either.