Just like one little nugget of anecdata. I used to work at a radio station in a small market that was 1/3 stations run out of the same building by the same owner, an older conservative woman who inherited the business. One station was all-talk (AM) one was country (FM) and the other was classic rock (FM).
All. Three. Stations. Had to carry Rush Limbaugh over the objections of FM program managers. Why? Because Alvina liked Rush. She wanted to blanket the airwaves with his show. And she didn't have to deal with any competition in the little corner of the world where the stations aired. People don't see those decisions, though.
Granted this is a particular egregious example, but by and large TV/radio/cable/etc. programming is at a macro level dictated by upper echelons of the business, not by the front-line reporters or editors.
Print publishing has been gutted over the past 20+ years by a lot of factors. (Radio even longer, see Clear Channel, et al.)
Consolidation. A move from print publishing to web publishing that has required more and more intrusive tracking and obsession with clicks -- not quality, just "how many page views?" and then "how many uniques?" or whatever the metric du jour happens to be. I've been on the publishing side and corporate side, and I've never once heard a company factor quality of content into its advertising decisions. Which means it's a race to the bottom -- not in terms of bias, but in terms of "what gets eyeballs?"
People love to bitch about the quality of journalism, etc. but yet... they keep consuming it. They certainly don't want to pay for good journalism. Not as individuals, not with corporate marketing dollars. If an ad buyer can get 10x the clicks and leads with crap than they can get with well-reasoned and well-researched content? They'll buy crap every time. And blame the journalists/press/publications for the quality and then do it all over again.
Not to mention the effects of Google and Facebook, which are hard to understate.
Google has done a huge number on publications that initially managed to navigate the print -> online model. Its dominance on online ads has done a lot to harm publications, and not only monetarily. Facebook has trained people to expect their information funneled through their feeds and has inserted itself between the audience and publications. Traffic that used to come directly to the publication now funnels through Facebook -- or never actually arrives at the publication at all. Hard to make a buck that way.
This isn't even getting into consolidation of local newspapers by conglomerates and private equity[1].
If front-line journalists are biased one way, I assure you the upper management through ownership are biased in the other direction by and large, excepting (perhaps) some social issues where bean-counters have seen that the winds have changed and it's more profitable to be visibly progressive vs. visibly conservative.
I went corporate a number of years ago because the writing was on the wall. If I'd stayed in publishing as a freelancer / writer / editor it would be years of paddling faster to make the same money. Companies didn't give two shits about quality, just shove something out the door that would play on social and/or SEO. If you think the people doing the work are deciding to embrace that, you're sorely mistaken.
[1] https://prospect.org/health/saving-free-press-private-equity...