If anything, "yellow journalism" has been the norm. Being a journalist used to be a step above parasite and ambulance chaser in popular opinion. You didn't need a college degree, let alone an Ivy league degree like today, to do it. Most papers were blatant mouthpieces of owners or certain political parties. Everyone knew that. "Objectivity" was laughed at by reporters.

That shifted with Watergate, which, afterwards, journalism began to have a certain prestige as "crusading truth seekers." Journalists doubled down on that view, cultivated it, and began to believe in it. Nowadays, journalism (at least in major markets) is more about prestige and access to power. Some journalists have a complex and believe that they have the access to the truth, leading to much handwringing about its "professionalism".

In reality, journalism is closer to writing in a journal after a party: they just offer accounts of events. That we expect better from them is, in part, a creation of their own making that is now starting to bite them in the ass.