At the initial time that the player left, there's a poor performance in the club in a few match but after which the club still bounce back to being strong, defensive and undefeated. Pulling out one or two superstar from a club can not just make the club to turn bad in all their competition.
because with the departure of a star player from a club, it does not always mean that the club will fade, but the club can and will create new players in their team so that the new players can show their game without being overshadowed by the previous main players and this can be used as a team overhaul with a new formation.
Like I already said, It doesn't happen all the time, some team can experience the impact just a few time but will have to adapt to the fact that they need to buckle up and defend their team but sometimes too, the impact is usually felt for a very long.