A Liverpool fan in work said the same thing to me. He said that City were a yo-yo club through our entire history. I told him that only Everton, Liverpool, United, Villa, and Arsenal have spent more time combined in the top flight league than City. United have only spent 4 years more combined than City in the top flight. If not for our late 1990s relegation craziness, then City would still to this day have been in more top flight seasons than United.
United spent nearly exactly half their pre world war II existence in the second tier of football. That's a fact that they don't talk about.
City spent most of their time pre world war II finishing above United. (City = 28 United = 15)
Liverpool spent a decade following world war II in the second tier, and only escaped after getting their own sugar daddy, again something that their fans don't like talking about.
City won the FA Cup 4 years before United and 61 years before Liverpool.
City won the League Cup 22 years before United and 4 years before Liverpool.
City were the 4th English team (Spurs-> West Ham -> United -> City) to win a European trophy via a UEFA tournament 3 years before Liverpool won a UEFA tournament
Rival fans who pretend that City were a Wycombe style rising, just don't know what the hell they're talking about. They're pathetic and jealous. They think that it hold themselves up as being great by trying to tear others down, ignoring the fact that they usually use incorrect information, or are straight up knowingly lying about what they're saying.
Fuck them.