I think that media at large (including biased, seemingly non biased, and established mainstream) have a problem with credibility because of bad editing habits. The headlines are designed to sell. This makes for a bad reading experience. Even SlashDot has been guilty of that, and of course harshly reprimanded when ti does. If news organizations want to be considered credible, they need to strive for their chosen profession's excellence standards, not use it to just lash out. (use the news force, Luke!). Some editors do a good job, most don't unfortunately (imho)
For the biased media outlets, I see a large part of the problem as it seems there an additional need just to get even exposure by using a 'fight fire with fire' mentality. i.e., "if the other side (alt-right) puts out fake news, then we have to just to be heard" sort of thing. It's wrong, of course, and suspicions rise from everywhere wondering if those are plants as well, or used to sway the unknowing or think it's funny because of the reactions they get. Didn't we call them 'trolling' articles before?
Snopes has been used a lot by both sides to denounce the other side's articles, which can explain their increased traffic more than complaining people are not fact-checking. "Who's facts are the real facts?" becomes an e-discovery in itself beyond the story you're trying to fact check. Complaining there are not enough news people (fact checkers, editing, etc) seems to be a cop-out for me. Then get better. Every industry deserves more support personnel and sometimes you have to wear two hats (like devops). Learn. Expand that knowledge of your profession. No one else will. The empty spots are a warning sign to a changing industry (from paper to ethernet). Adapt to survive....or change careers.