It's not the economy blablabla. It's good management or not so good managment.

How McDonald's Is Winning More Than the Value Wars - @Advertising Age
By Emily Bryson York Published: May 12, 2009

CHICAGO (AdAge.com) -- It wasn't enough that McDonald's is beating competitors in same-store sales and winning the value-perception wars. Thanks to stepped-up burger marketing, it's now getting higher-margin customers, too.

While McDonald's pretty much owns the value menu and pricing proposition, since last summer it's quietly boosted advertising of full-priced items, which is paying off by bringing in higher-ticket customers. The product-specific pushes, for Big Mac in July, chicken nuggets in December and the Quarter Pounder with cheese in February, have resulted in double-digit sales increases for the products in question."