As I understand, some big collectors has two set of 5131 all models. Look at this picture from Google search. The owner has a set of 4 5077 and double sealed.
Some collectors keep contribute a lot every year in order to get more rare watches they like. Collector may not want to spend more money if he can't have the watch he likes. I guess how many rare watches to collect is deponding on how much of contribution.
