There is something to be said about having the same people in charge for a while. This gives the leader of the team a chance to develop a team over a couple of years. Look at Andy Reid in Philly and Sir Alex at Manchester United, both have been at the job for a while and had great success.
But at Manchester City, having a leadership structure in place for a while is something that they want no part of. After City thrilling 4-3 win over Sunderland, the City leadership decided to sack Mark Hughes in favor of Italian Roberto Mancini. This makes no sense for several reasons, I would not say that Hughes has been super but Hughes is still in the process of building a team and it seems to be working.
If the City leadership had allowed Sparky to say they might have been closer to being part of the Champions League then they are now that they have shown Sparky the door. Mancini will now come and try to overhaul the team, so the building process will again start over.
The thing with City is that over the last decade no youth team setup has produced the number of players that they have. While they have the money to spend on players they also have an outstanding academy. With the money and academy that they have there is no reason that they should not be part of the Champions League in the next couple of years.
The main reason that will not happen is because of the leadership of the Manchester City playing musical chairs with their managers. Stick with one guy and let him develop the type of team that he needs to be successful, just like Hughes was doing, but that was not good enough.