More risk, more reward - it's usually that simple. That last example is closer to the security of a job than the lottery I'd say :) The likelihood of getting fired from a job is probably not that much lower than a plumbing business not working in an underserved area.

I've built a pretty low risk business to get cash flow going and am starting to tackle more high risk stuff. There's safe strategies to play the lottery in a way where you can afford to lose.