I never said Colbert wasn't doing Bill O'Reilly, I was saying he added to the character, things that were not specific to mocking conservative punditry, just making him more of an overall blowhard or Ted Baxter. Colbert himself said he added some Keith Olbermann and such to his persona to keep it fresh as he didn't think the O'Reilly parody could last. And I think the show did drift away from specifically targeting O'Reilly and conservative punditry in the later years of the show because Colbert had by then created a whole complete character who had evolved past mere parody into his own creature. Sure, he was still a conservative, but lots of the aspects of the character were not deliberately mirrors of conservatives but instead parts of the Colbert character himself now.