Why did these A-list stars and/or one time up and comers fall off in the first place?

[TMC1982]

Of course, some of these actors are still working but they aren't any where close to where they were during their "glory days" as bankable stars or when they were hyped as the next big thing. Some's fall from grace may be more obvious than others (drugs, egos, ageism, too many box office bombs in a row, Harvey Weinstein), but it still worth the discussion for why some actors' relevancy in Hollywood and impact last while others ultimately fade.