Is Simcity 5 not on steam?
At the moment, Simcity 5 is not on steam. There are also no details as to whether it will be there or not. You need to log in to the games official website so as to receive any updates.
It's not currently offered via Steam, nor have any plans to do so been released. As far as I know you have to play it via Origin directly.
I havent seen any promotions for it on the store page of steam, but i dont go there often