Brain Drain

Groups such as countries, corporations and Ancient Conspiracies need a lot of talented people in order to function. One way to get that is to recruit from each other. This can easily result in one of them just keep sliding backwards, losing their competent and talented people to others and thus becoming less and less competent and talented as a group.

This phenomenon is quite widespread in Real Life, as the other Wiki can testify.

In a way, Brain Drain is the opposite of The Peter Principle. However these are opposites that happily coexist and help each other making life a living hell for those who remain: The talanted move on elsewhere, while the less talented gets promoted to positions they are incompetent for - which can easily lead to becoming a Pointy-Haired Boss.

In individual cases, The Peter Principle can also be used to subvert Brain Drain - as it turns out that the new guy wasn't so talented after all.

Literature

 * In Atlas Shrugged this is
 * In Unseen Academicals, Braseneck College seems to be trying this on Unseen University; their Archchancellor is the former Dean, and their Ponder Stibbons equivalent used to be Ponder's best student. They even offered Ponder the post of Bursar, but he never even asked what the salary was.

Newspaper Comics

 * In Dilbert, the protagonist works at a company that always seem to be at the losing end of this. Except if you've been there for too long (like Dilbert and Co.) because this company is a black spot on resumes.

Tabletop Games

 * A common theme in Mage: The Ascension is how the various Traditions and Conventions try to recruit talented Mages from each other.
 * Forgotten Realms: Knights of the Golden Rooster in Raven's Bluff often complain that other knightly orders tend to "take their best". Or, looking from the other end, being an "entry-level" order for common people and adventurers and a route to higher responsibilities is one of the Roosters' main roles.
 * Battlefleet Gothic, of all things — and among the Orks of all people. Leadership (crew competence and morale) is randomly generated, but the Ork battlecruiser and battleships have a special rule: they "can opt to swap Leadership ratings with a Kill kroozer or Terror ship to represent the warlord dragooning the best crew in the fleet aboard his vessel".

Real Life

 * During a given countries "golden age" it has often been common for adventurous immigrants to swarm over there to find opportunities. For instance, several conquerors have had scholars and artists crowding their courts simply because the prestige attracts. This naturally causes a Brain Drain in other countries.
 * By the same principle, countries going through particularly bad times experience an exodus of the talented to anywhere else, which naturally makes ending those bad times more difficult. Perhaps the most famous example of this phenomenon is the Berlin Wall, which was in large part erected to prevent skilled people from leaving East Germany (and instead had the unintended effect of keeping precisely those people in East Germany who were unskilled at climbing walls).

Web Comics

 * The Adventures of Dr. McNinja: King Radical and his Mafia prevent the brain drain from occuring in Cumberland, MD, by encouraging high school and college graduates to stay in the area. Very strongly encouraging.

Western Animation

 * In one episode of the animated version of Dilbert, the protagonist manages to get recruited by Nirvana Corporation, the great company that's always steals the best and brightest from his old company.
 * On The Simpsons a company tried to hire away Smithers but he wouldn't go for it so they tried the employee with the next highest seniority (and therefore obviously the next best guy) - Homer.
 * He actually was a hugely valuable employee for them, his wacky ideas were given a fair try and made the people he managed more productive.

Video Games

 * In the Interactive Fiction game The Lost Spellmaker, all of the spellmakers (people who, well... make spells, for the entertainment of the masses) from the PC's town and the other villages nearby are mysteriously disappearing. It turns out they're being stolen by the nearby city of Plantasitoy. Given that Plantasitoy is, one could easily read this as a metaphor.