How did Ray Croc become wealthy?

[Starmix]

Ray Croc was not the original inventor of the McDonald’s hamburger, but he saw the potential in the brother's efficient, assembly-line approach to making food. He brought their franchise rights, and with aggressive, marketing and expansion, transformed McDonald’s into a global empire.

Kroc’s genius was in recognizing the power of franchising. He allowed others to keep McDonald’s restaurants under his strict standards, which applied to rapid growth and control over the brand. He started this business at the age of 52.