As Biden's approvals/re-elect numbers drop in polls, journalists will be lining up to join Team Trump. There are careers to be had! Books to sell!
People say "it was always thus" but people tend to say that about anything. Sure that journalists often root for the guys they're covering is not a new thing (everyone points to Boys on the Bus), but I think the career incentives are extremely obvious now. That's on top of latent sympathies, of course.