These media luminaries were just right for the archetypal parts they inhabited for so many years — roles that not only made them big names in broadcasting but also took them to the forefront of the national political discussion.

One by one, they have fallen to a range of allegations of sexual misconduct against them — the latest coming against Mr. Lauer and Mr. Keillor on Wednesday. And their sudden loss of stature is stripping away their television personae and swiftly ripping down the edifice of the old television news patriarchy in the process.

For their networks, these stars, whose talent for storytelling was matched by their ability to charm audiences, were money in the bank. They also drew salaries that were commensurate to how important they were to their bosses’ budgets. Mr. Lauer and Mr. O’Reilly each made more than $20 million.

The size of those investments would have provided their networks with ample motive to turn a blind eye to their alleged misdeeds. And NBC and CBS, like Fox News before them, now face questions about where their managerial systems broke down — as they inarguably did — to allow such sickening behavior to go unaddressed in ways that allowed the offenses to repeat themselves over years.

The arrival of hard consequences for these men may have come too late in the news industry, but media organizations are unquestionably leading the national reckoning now underway.