Or for another "white-collar" example: the alleged "pilot shortage" in the US. There's no shortage of trained, qualified pilots; there is a shortage of trained, qualified pilots willing to accept the wages and working conditions that are typical when starting out with a US-based airline. That one ends up draining in the opposite direction: instead of working for airlines in the US, those pilots go overseas where the offered pay and working conditions are better, and end up flying for Asian or Middle Eastern airlines.