C.H.I.P is gone now and Raspberry Pi makes no money on their 5$ version but has enough sales to break even and use it as a loss leader (Educational purposes). Each platform supports different functions. Did you know you could have up to 5 Ethernet ports on the Omega and it supports native soft AP to act like a router / hub? There are no Ethernet ports and NO WiFi on the Pi Zero.
There are a lot of things to consider besides price like application, use case, size, ect.