Well, no they certainly don't have the best interests of America at heart but mostly they're driven by greed. The owners of US newspapers are generally happy to give their news in liberal cities a liberal slant and their news in conservative cities a conservative slant. The problem used to be a lot more intense than it is now with competing newspapers being mouthpieces for competing political parties. But the rise of national broadcasting and the resultant economies of scale meant that the networks had to move to compromise coverage.

There's certainly something to be said for giving people the sort of news coverage that's good for them instead of the sort they want. Not reporting on disasters until all the facts are in. Never mentioning the names of mass murderers who are after fame. More statistics and less anecdote. But if given a choice the bad media will drive out the good (mostly).

You could solve the problem if you had a reliable source of philosopher kings we could set to rule over us. Until we find one I think we'll have to do with giving the people what they want. It's far from optimal but at least it corrects quickly when things go badly which is a lot more than you can say for most other things people have attempted.