Certainly, joining a start-up as an employee "to get rich" would be the wrong idea. But I imagine many of us here are founders, and though we're not doing our start-ups for the sole purpose of getting rich, the fact that it's a possibility is certainly important. Would you bother working on your start-up if you knew for sure that it would never make you more money than you could make burger-flipping? (directly or indirectly)
I think it's important to note that there are different stages of a startup's lifecycle. It's been my experience that venture funded startups aren't nearly as risky as people make them out to be.
My guess is that the typical venture funded startup has a lifespan of at least 4 years. That's probably close to how long the typical college grad will want/should stay at their first job.
Bottom line: join a startup, don't start one.
