Contrary to popular belief, Manchester City don't have a big squad.
Pep Guardiola does not like to have huge numbers of players like Chelsea had last season because he prefers working with a smaller group that he can be closer with and not have to disappoint more on a regular basis by leaving them out of the team. If it was Jose Mourinho that made two players for every position seem the idea, the City coach much prefers fewer players who can cover several positions.
That means that great thought is taken when any additions are made to the squad: the question that is always asked is how can they improve on what is already there? When what is already there has just won a Treble, it is even harder to answer.