Of course, it's hard to fathom that the 56% of Americans who describe themselves as moderate or liberal are watching O'Reilly, and he seems to be doing pretty well for himself.
But the larger issue here is O'Reilly's assertion that "Colbert has built an entire career on pleasing the left" -- which is true, but neatly omits a rather pointed and glaring subtext, which is that Colbert has done so by, specifically, lampooning Bill O'Reilly.
Back in 2005 when "The Colbert Report" debuted, Colbert made it clear to The New York Times that O'Reilly was a major inspiration for his conservative blowhard "Stephen Colbert" character. As Jacques Steinberg wrote in the Times,
"Though not intended to feature a dead-on impersonation of Mr. O'Reilly, 'The Colbert Report' will have the feel of 'The O'Reilly Factor,' with an outspoken host delivering blunt opinions, some of them illustrated by graphics -- Mr. O'Reilly calls them 'talking points' -- that are the equivalent of captions for the impaired, emphasizing what the host is trying to communicate."
And in 2012, Colbert, in an Oprah Winfrey interview on OWN, reiterated that O'Reilly was a key inspiration for his show, and then went further: "We wanted to do something that was a pundit show where the character was [a] well-intentioned -- I like to say that he's well-intentioned -- poorly informed, high-status idiot."
The Oprah interview included an archival clip from "The Colbert Report" in which Colbert responded to a New York Post "Page Six" gossip item claiming that O'Reilly had been overheard telling pals that he's a fan of Colbert's show. "Backatcha, Papa Bear," said Colbert. "If it wasn't for you, this show wouldn't exist."
So let's take a moment to think about poor Bill O'Reilly. We are, all of us, losing "The Colbert Report" -- and, reportedly, the "Stephen Colbert" character -- when Stephen Colbert heads over to CBS to take over the "Late Show," but O'Reilly is losing something much more profound: his very own satirical doppelganger.
How should Bill O'Reilly react? How should Bill O'Reilly feel? At which point along the Kübler-Ross model -- the so-called five stages of grief -- is Bill O'Reilly right now, and where will he take us next?
Place your bets, as the man says.
Simon Dumenco is the "Media Guy" columnist for Advertising Age. You can follow him on Twitter @simondumenco.