The Super Bowl is always a "likely target" every single year, just like the World Series or other large gatherings of crowds, such as Times Square at New Year's Eve. It's been that way every single year since 9/11.
And yet nothing happens.
Did our intelligence ops stop attacks from commencing, or were they never planned in the first place?
One of the main points of terror is to strike where people feel safe and are vulnerable. Security is always high at the obvious places, and too many people are on guard because they just expect there to be trouble.
Safe and vulnerable.
That's where terrorists are most likely to strike. Not at well-guarded and protected places.