The closing of the casino's reflect a downward trend in people wanting to gamble at AC. There are other places that are closer for true gamblers. AC never had any other attractions to draw people, other than the boardwalk, but that was at the turn of the 20th century.
Just like any former popular place when patrons decide to take their business, somewhere else. Nothing more, nothing less.
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"It doesn't cost "nuttin", to be nice". 
MOM
I just want to do the right thing! Uncle Joe, (my hero).