> Assuming a robust job market Bad assumption. I've known people who lost a large chunk of their retirement funds in the dot-com bubble, despite "diversifying

> Assuming a robust job market Bad assumption. I've known people who lost a large chunk of their retirement funds in the dot-com bubble, despite "diversifying" within it. More recently, there was the housing bubble. Both of these had implications for the job market - and salaries - at the same time. Some people would argue we're in the middle of a tech, games, or VC bubble - and while they might be wrong, diversification is what you do to mitigate the risk in case they're right.