Manchester City has been performing well in the Premier League for a long time, but this is not the case. Basically, since Guardiola took charge of Manchester City, Manchester City's performance has started to change and under this manager, Manchester City has won the English Premier League title several times and has a Champions League title to their credit.
Since Manchester City has performed well consistently for several seasons, it is natural that Manchester City's fans have increased recently. Last season, we saw Liverpool perform well and Liverpool has long been doing well in other tournaments including the Premier League Champions League and I think Liverpool will be ahead of Manchester City in terms of club popularity.
So when the two teams with the most fans in the Premier League perform well, it is natural that the fans of those two teams will discuss their matches and speak for the teams.
It's nice you have acknowledged that Manchester City has been performing at the top for several seasons in recent years, which was also where I concentrated on. In this same recent years, Liverpool has won 2 EPL titles and one UCL while Manchester City has 6 EPL and one Champions league, in the same recent years Chelsea has 1 EPL, one UCL and one CWC of which they just won few weeks ago. By contrast among these teams, Manchester City still has more in the last ten years. So if any club fans should be noisy, it should be Manchester City fans.
You're right Manchester City has been one of the best performing team in the Premier League in the past 10 years they've win the league consecutively compared to others Liverpool and Chelsea have been good too especially Chelsea that won a major trophy recently but they still can't be compared to Manchester City in the past few years City has dominated the League more than any other team.