Although, we just took on an intern who absolutely kicks ass, and runs circles around people who've been doing it for 10 years. That kid makes me nervous lol.
It's at least partially because it's so many programmers' "dream job." So many people get into programming because of their interest in games, then take jobs in the industry. They then are willing to tolerate/justify worse working conditions because they are doing something they are passionate about and the company culture has evolved to exploit that.
Theory: Because people like developing games, the industry has gotten used to overworking workers and replacing them with fresh meat once they burn out. There's more than enough replacements eager to work on games.