NBC News has long been a dominant presence on network television, regularly winning the ratings competition against its evening news and Sunday morning political show competitors, and reveling in the “Today” show’s 16-year winning streak in morning television, a record not broken until April.

Struggling with declining ratings across all three franchises, however, and with news this week that the network is preparing to replace Ann Curry on “Today,” NBC executives are facing a new narrative that is being embraced by the competition. For the first time in more than a decade, NBC News appears adrift.