>Because they all auditioned and tried out for the show and got picked.
Then, a whole bunch of people tuned in, making it MTV's Highest rated show ever.......ensuring it would have gone on FOREVER, had not Snooki gotten pregnant, and kinda ruined the dynamic.
Then Hurricane Sandy wiped out the Broadwalk and half of Seaside........so, that pretty much ended that.
Why is any tv star famous.???? Because people tune into the show and make it a "hit".
Where would the cast of Seinfeld be right now, if it was canceled the first season because no one tuned in? They're famous because viewers made them famous-.....ensuring their huge paychecks.