Not all sky blue, we were the first and wore it for most of the 15 seasons before they ever wore it. In the 60s and 70s everyone knew we were the sky blues, Manchester City were NEVER called that. Your argument is that we shouldn't copy them because they are now considered the sky blues by the sky generation. We aren't copying them, they copied us. That is why it is a weak argument.
My brother in law is a 66 year old Manchester City fan who has watched them from the 60s and he has never referred to them as the sky blues. I have known him for 33 years and talked football with him numerous times. Plus, they don't play in all sky blue.
This is a generation thing, I think. If you started watching football in the 80s or 90s you see us as a stripy team. If you are of an earlier vintage we're the all sky blues.