THE success of the Golden Arches rests on three simple, sturdy foundations: a menu of reliably decent grub, at a decent price, shored up by catchy marketing. Ever since it went public in 1965, McDonald’s has done best whenever it stuck to this original blueprint. When one or more of these pillars crumbles, the fast-food fortress looks shaky. A quarter of a century ago this led to a near-collapse. Overly rapid expansion in the number of outlets and, at the same time, of products on offer made it harder for burger-flippers to keep up, hurting reliability. A price war with Burger King turned downright indecent. And the ads were stale, too. The result was acid reflux for investors. Between late 1999 and early 2003 the company shed two-thirds of its market value.