Definitely not the case. In Salford, Cheshire, South Manchester etc you'd really struggle to find anyone who was a city fan. Source: I lived in Ashton-under-lyne from 1990-1995 or so. I personally knew literally hundreds of United fans (and this is before their really dominant era). During that time I knew literally 1 person who was a city fan and everyone would relentlessly take the piss out of him for it.
How do you personally know hundreds of people well enough to know about which football team they're supporters of?
Its really not difficult at all. Especially in Manchester.
Thats just not true. In fact until very recently Unitedwere by far the more popular team in this city, the meme came about as they have so many fans from outside the city as well.
Also, to the poster who mentioned Stone Roses, No, they are united fans.
In fact until Oasis the only celebrity city fans were bernard manning and curly watts from corrie