The fast-food industry is notorious for employing millions of Americans at poverty wages.

Fast food also has a uniquely difficult business structure for workers to achieve better wages and working conditions.

The minimum wage isn't earned only by people working at fast food restaurants and in service industry work - the average income for positions like nursing assistants, preschool teachers and paramedics are all under $15.

The free market hasn't done a very good job "figuring out" how to pay workers enough. If it was solely up to the market, the people with the least power would be paid pennies ... or less.

The vast majority (over 80 percent) of fast-food and similar low wage service jobs (<$9.24/hr) are held by adults. A quarter are adults over 40. Another quarter are moms raising kids.

Most fast-food workers can't easily join a union, because they don't work directly for their parent company, such as McDonald's or Subway. Instead, they work for individual franchise owners, ensuring that each individual fast-food outlet would have to organize and win union recognition separately. So there's not one central employer to bargain with, as in a traditional union campaign.

When families can afford the basics, they can reinvest in their communities, and higher wages means a broader consumer base for businesses.