Nostalgia is a hard concept to explain especially to a young audience that prefers forward facing purpose driven brands including fast food. Here’s what I shared about McDonald’s return of The Hamburglar and KFCs revitalization of the Colonel with Sydney Ember at The New York Times:
http://www.nytimes.com/2015/05/23/business/media/hamburglar-mcdonalds-colonel-sanders-kfc.html?_r=0