The limiting effect on the three top teams with managerial changes is being grossly over-estimated here. Not all managerial changes in summer lead to malignant instability or poor performances.
Chelsea have been having a managerial change every year and they have arguably the best of the lot back with them. City had a terrible season last year and failed to achieve any of their objectives - I can't see them having a worse season than last under Pellegrini.
The only ones who will be genuinely affected are Manchester United. Even there, I expect Moyes to fail (not match up to Fergie) in squad-building and getting the best out of young players. They might have some consistency problems but will not fade away from the title scene, so early, for sure.
So, we're the ones who have the onus to pick ourselves up if we want to compete for the title. Which has been the case in the past few years, as well.