Definitely deja vu…. has been a topic for as long as I can think back.
Also, what may be of interest is the % of players that are new versus several months old.
While I obviously agree that it is up to the casino to make players happy enough to stay loyal, there are types of players that will never stick.
Different sites attract different types of players, depending on traffic source and promos used. That plays a role in retention too.