Obviously there will be (a) pressure from flat owners to keep ground rent down, and (b) inefficiency in how ground rent is spent, compared to how building owner

Obviously there will be (a) pressure from flat owners to keep ground rent down, and (b) inefficiency in how ground rent is spent, compared to how building owner would spend it. The dynamics for both things are exactly as described. This is slowly evolving story, at some point most apartment are no longer used by original buyers but by their children or grandchildren.