Millennials Are Threatening The World's Most Powerful Brands

The shifting values of people in their 20s and 30s are threatening some of the biggest U.S. brands.

Iconic brands like Tide, Levi's, Coca-Cola, Ralph Lauren, Gap, and more "are going to suffer a precipitous decline in relevance, in sales, and share of market; or drop dead, at the very least," retail expert Robin Lewis writes on his blog.

The advent of the Internet and e-commerce has taken price competition to the extreme, with big retailers scrambling to get consumers' attention and offer the lowest price.

"Over time, these practices erode value, either in reality by taking quality (costs) out of the brand, or simply through compromising consumers' perception of the brand, thereby tarnishing retailers' integrity and image," Lewis writes.

Fatigued by constant marketing and advertisements, young people are drawn to the simpler marketplace enjoyed by their grandparents, Lewis explains.

Over time, consumer culture began encouraging "quantity over quality."

But millennials crave authenticity and craftsmanship, according to Lewis. They also prefer understated products over conspicuous consumption.

Huge brands like McDonald's and Wal-Mart have reportedly had trouble connecting with millennials.

McDonald's launched new menu items like a healthier snack wrap, while Wal-Mart is investing in smaller marketplaces over Supercenters.