It's likely that every major star of today, good and bad, has at one point benefited from this.Women seem more affected by this than men, perhaps as a result of roles and stardom coming to the most recent pretty new girl on the scene.
Compare Deader Than Disco, Hype Aversion, Hype Backlash, Music Is Politics.
Also compare it to the "star system" employed by the studios during The Golden Age of Hollywood, which this is effectively a modernized version of.
The Hollywood Hype Machine refers to the massive set-up that is in place to create said new stars, or new TV shows, books or movies. Well, the star will linger for a year or two before disappearing, as people wonder "what the hell ever happened to...? At best, they will continue working in indie flicks, low-key studio pictures, and television, and may even be able to mount a comeback later.
An aspiring, good-looking young actor, after getting a few noteworthy roles in indie films, TV shows, or their home country under his or her belt, will be chosen by a studio to be the "Next Big Thing" (or "It Girl" if female) and will thus get a major headlining role. Men's/women's interest magazines will be lining up to offer them a sexy photo shoot. At worst, they will be in rehab, unemployment lines, and "Where Are They Now? Sometimes, even if they're successful, the actors may get overwhelmed and suffer public burn-outs, become typecast or too associated with a particular role, or simply reject Hollywood for a normal life.
As the female stars age, Hollywood decides they aren't pretty enough anymore, and casts the new young thing.