Why hasn't Damian Lewis or Sarah Shahi been on Late Night With Conan O'Brien or the Jay Leno show?

I asked this last November and sadly, it still applies. If those shows have any reason to exist, it's to whore for NBC series. So where's the service?

I'm thinking of this now because The Riches has been cancelled. IMO this is another show that, like Dirt (also on FX), was potentially great but got shot down by the writers' strike.

But, at least I can't claim the network didn't support The Riches. Eddie Izzard & Minnie Driver were all over the talk shows, and there were ads for both seasons all over TV.

I can't say that about Life, starring Lewis and Shahi, which is doing badly in the ratings. Besides its total invisibility on the late-night talk shows, the only ads I've seen for it have been online.