Answer valid through Xcode 7, 8, 9, 10, 11 and 12+
You can not archive, because from target you have not selected device or Generic iOS device or Any iOS Device , still there is a simulator.
Nothing generic or wrong with Xcode 7. This happens with all Xcode versions.
- Problem – Why archived button is grayed out?

- Solution – Why archived button is not grayed out?

In Xcode 12 it is named Any iOS Device
