Most news sites rely only on advertising for income. Real reporting and investigation costs money. Since their main money source is now drying up, news is starting to become hearsay, rumors, and things you see on Twitter (anything you can find from the comfort of an office chair). This quickly leads to a race to the most clicks, which may or may not be factual.
We also are now starting to see blogs and many other news sites switch from advertisements on the side or top (which can be blocked) to entirely sponsored articles written around a product or service. We've always had sponsored articles, but not as prevalent as it is now.
Real journalism costs money. When you remove the only way to fund it, we end up with what we have now: fake news passing as real journalism and fake articles which are actually advertisements.