Just remove the financial incentive to provide news. Or forbid "news" channels to have commentary. Just boring reporting of the news. Not inhibiting free speech, just requiring anything labeled "news" to provide nothing but news. Actual journalism. Reporting of facts with proof/evidence. No op-eds.
Get the greedy fucks out of the business.
MSNBC: 12 people died in an explosion yesterday, in Kabul.
FOXNews: 12 people died in an explosion yesterday, in Kabul.
CNN: please watch us 12 people died in an explosion yesterday, in Kabul.
.
You can only fix the news channels if you make each one irrelevant. No reason to watch any particular one, nor avoid any one. Don't even measure the ratings. Make that irrelevant. No commercials. Boring, factual, actual news.