Pretty much every local newspaper has been bought up and now almost exclusively talks about ads... err.. I mean national issues. And it isn't even articles that these papers write, rather just the same article published by someone like The McClatchy Company.
Same thing happened to broadcast news.
Big print newspapers were mostly independent and subscriber-funded, so they answered to their subs rather than advertisers.
The Economist is still independent and subscriber-funded. But, most sub-driven publications now have to fight tooth and nail to stay above water, so the writing needs to be tailored towards engagement/clicks :/
There was also more a desire to serve public interests prior to Reagan getting rid of the rules on media consolidation. It wasn’t perfect but it was much better than what we have now. News media is much more beholden to corporate interests now than in the past.
This has never (really) been the case with "mainstream" media. "The media" in common parlance is a farce. Historical news has almost always been agenda driven, and was key to the American revolution, Labor reforms in the US, etc. Those things are not "mainstream media."