I'm guessing it's because there REALLY isn't much of a fervor this year for Superbowl 2025. It's a REALLY lackluster Superbowl year, one of the lowest anticipated SB's in History.
Where are you getting this information from? This will be in the top three most-watched Super Bowls. I wouldn't be surprised if it ended up being the number one, but doubtful, perhaps a number two spot.