I remember reading a theory on this that basically it is a symptom of the decline of the news media industry. The positive attitude in the industry lined up with good times for them until around 2000 when their revenue peaked: https://compote.slate.com/images/42207fae-3603-4fe5-b4fe-a65...

For them it really is doom and gloom, and they spread it to the rest of society like a contagion by their writing much like the the banking crisis in 2008 poisoned the entire economy.

I'm not sure if it's true, but it makes a lot of sense to me.