Or maybe it's the reverse, because the field has high prestige and impact, it attracts upper class children who don't need the salary, causing a downward pressure for journalist wages.
"How journalism became a middle class profession for university graduates": https://www.theguardian.com/media/greenslade/2009/jul/21/new...
"The death of the working class reporter": https://blog.usejournal.com/the-death-of-the-working-class-r...
The original claim I was challenging was "journalists in particular no longer find themselves in the upper middle class" -- I don't think they ever were, it's possible that MORE of them are now than previous -- as you say, even as salaries drop.
This article is just standard journalistic myth-making. The journalists cited as examples of success without college degrees, Carl Bernstein and Walter Cronkite (who both went to college, just dropped out), came from privileged backgrounds just like the privileged kids who fill the industy today.
Maybe 10-15 years ago that was true, but today the control of public discourse is no longer controlled by the elite class. Blogging completely ended that control.