What's more, millennials aren't the only group to adopt digital and mobile technologies, including 34 percent of online shoppers who are older than 65 and own a smartphone.
"Misleading media and hype lead [online business] executives to believe that these changes are somehow different from anything that's happened before, and that they must address these generational variances immediately or perish," Forrester analyst Sucharita Mulpuru said. "That perception is misguided at best, false at worst."
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Retailers from Whole Foods to Macy's have been tweaking their business strategies to attract a younger shopper. Whole Foods said last month that it will launch a new, low-cost grocery format that caters to millennials; Macy's is testing an off-price concept and beefing up its millennial-facing wedding category.
But transforming a company's business plan to reach this group may not be worth it, Mulpuru said. For one, millennials are financially strapped. Households under the age of 25 shelled out 7 percent of their total spending on education in 2013, up from 1 percent in 1973.
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They've also experienced more decline in real income than any other age group over that time frame. Compare that to the purchasing power of people ages 55 and older who, according to a recent report by FBIC, control more than three-fourths of the country's household net wealth.
For another, attracting consumers at a young age no longer has the long-term benefits of creating a "customer for life"—something Mulpuru said doesn't exist in today's hypercompetitive retail landscape. According to Forrester, there were nearly twice as many bricks-and-mortar stores in 2014 as there were in 2002.