Yeah I dunno how legit Forbe's valuations are, they were just the ones at the top of the google search. *shrug*
CNN had an article about the "other" teams catching up with the Yankees in payroll, so I think you're hitting the nail on the head with the changing nature of baseball's media contracts. I know the Reds are negotiating in a year or two for new TV rights. I just hope they get what they need so Votto isn't the only star on the team in 3 years.
Marlins, Angels help shrink payroll gap in Major League Baseball - MLB - SI.com