In Rockford, Ill., one noon hour last week, a cooked-out housewife packed her three small children into the family car and set her course for a peppermint-striped glass-and-tile structure boasting a huge sign: MCDONALD'S HAMBURGERS. Stepping up to the self-service window, she ordered four hamburgers and milk shakes. Just 41 seconds and $1.40 later (hamburgers, 15¢; shakes, 20¢), she was on her way back to her waiting brood carrying an instant lunch.
On the strength of such low-priced assembly-line feeding, Ray A. Kroc, 59, has built his Chicago-based McDonald's Corp. in less than...