Not sure how we can determine if it is the most collected item . The SDCC is a huge metric, as to the popularity of the medium. We don't see turnouts like that at train, stamp, antiquarian book or any other type of collectible event. But let's face it, the current comic con landscape is more about pop culture and movie starts now, than it is about comic books and the artists. The MCU has given a HUGE boost to the comic world. I have a Captain America wallet, and at least once a week, a cashier at a store will say 'cool wallet'. I don't think that reaction would have happened 25 years ago.