What took NBC so long? That's the only question that came to mind when I saw that Geraldine Laybourne, at long last, had sold her struggling women's cable-TV channel to NBC Universal for $925 million. The fact that I'm describing it as, yes, a "cable-TV channel" speaks to Oxygen's failure. Conceived in 2000 as a multimedia empire that would bridge the Web and TV, Oxygen failed to thrive in either medium. Backer Oprah Winfrey, Laybourne disclosed to Advertising Age, quietly backed out of the venture some time ago. For NBC, Oxygen is a natural add-on, a minor expansion of its cable lineup. As for Oxygen.com, it, too, is far smaller than NBC's iVillage, which NBC has struggled to integrate. Eventually, the Peacock may figure out how to merge its disparate networks — broadcast, cable, and Web, But if it was hoping to buy a recipe for doing so from Laybourne, NBC will just be cooking up disaster.