Are conservative publishing imprints past their sell-by date?

As a follow-up to this post on Mary Matalin's Threshold imprint, a reader who has some knowledge of these things writes to say that "Matalin's imprint has been a colossal flop" sucking "millions of Simon & Schuster’s dollars down the right-wing rathole." A quick web-trawl doesn't really help one substantiate this claim, but as I say, this snippet comes from a reliably conservative source who has contacts in the book business.