I never really gave it much thought either why local stations have 2 anchors at the desk, regardless if it's ABC 7, NBC 5, CBS 2, WGN 9 & FOX 32, the local news shops in this market. I think there are dual anchors in other local markets across America as well as on 24/7 news channels such as CNN & FOX News Channel nationally.

I know on weekend nights, there are solo anchors locally at the desk as well as nationally. I don't know if the business of news figures into the equation why there's 1 anchor on NBC 5, CBS 2 & FOX 32 on Saturday nights, considered to be a TV graveyard and a night when many people go out.

I don't know if local news shops want to pay 2 anchors on Saturday & Sunday nights as compared to the rest of the week. Just a guess on my part.