We're not making our money on Fair Trade coffee. I'm a heretic here - I think it is a niche product. The money is in regular and flavored coffees.
As far as sustaining lifestyles, it ain't the coffee as much as it is scale.
A friend was in a negotiation about his company with Bill Gates and my friend thought Bill was the biggest... rectum. The reason was that he kept pushing a single point for the whole hour they were together. "Why would 100 million people be interested in the product?" It was a high end video conferencing system that had a niche market of Global 500 execs. That was 6 years ago and it still is a stand alone company. Not worth Bill's time or money.
At home, I'm a die hard Mac user, so I won't concede that Windows is a superior product - it is an appliance, the toaster of operating systems. But Microsoft does have a bigger market share. And Bill is richer than Steve Jobs by a long, long shot. Starbucks is close to 18 times our size for much the same reason. They figured something out we haven't.
So why would 100 million people be interested in your product? If money is what you care about - for whatever reason - that's the question to ask.
If happiness is what you care about, then there is a different question. (If you find the question or the answer, please let me know.)
If the perfect espresso is what you care about, then...