As people get older, their brand loyalties are more set. Younger, working folk often don't have the house/family/healthcare/retirement worries of older workers. Marketers often target young folks because they'll spend on new things.

The Millennials are the largest adult demographic: http://www.indexmundi.com/united_states/age_structure.html . Their children will be bigger than them (hopefully!).

People of all ages don't always fit into the "generational" niche the media and marketers try to put them in to.