“Pushing Daisies” has joined a long list of returning genre shows clocking in at far more disappointing numbers than expected after its premiere was beaten out by none other than “Knight Rider” on NBC. The ABC series earned a 4.1 rating/7 share Wednesday, being easily bested by “Knight Rider’s” 4.6/7, revealed Fast National ratings from Nielsen Media Research. It was ABC’s worst-performing show for the night, thanks to a 34 percent audience boost from its lead-out, “Private Practice,” and a 4.8/8 from “Dirty Sexy Money.” That is the smallest audience that has ever tuned in for an episode of “Pushing Daisies,” nearly 13 percent less than its worst rating last season. It’s also down 35 percent from its first season average of 6.3/10, which made it the genre’s third-highest ranking …