Amazon CEO Jeff Bezos has enjoyed one of the most impressive decades ever in the tech industry, but a former Apple retail chief believes Bezos's fun is about to come to an end.

Speaking to Yahoo Finance in a recent interview, former Apple retail chief and JCPenney CEO Ron Johnson said he believes Amazon is in for a "tough" decade as it prepares to battle it out online and amid the brick-and-mortar with big-box alternatives.

"They're on their heels," Johnson said. "They barely make money in their online store, and Target, Walmart are growing faster."

It's a tough argument to make. Target and Walmart are indeed growing, and they're doing it by building their online stores, as well as their BOPIS business--a term used to describe customers who buy online, and pick up their products in-store.

But Amazon is still the biggest e-commerce retailer in the U.S. And with help from third-party sellers offering products through the company's Marketplace store, it's able to offer a wide variety of products at varied prices.

For his part, Johnson has some serious experience in retail. He served as head of Apple's retail division before he left for JCPenney in 2011. There, he tried to revive the retailer's ailing business and create a more successful brick-and-mortar operation. His efforts didn't work and in 2012, JCPenney had what some critics called "the worst quarter in retail history."

Johnson was fired in 2013.

Since then, Johnson has been trying to build out his own online company, called Enjoy. The company offers same-day delivery on tech products, and offers in-home setup, so people can get their products up and running without any trouble. 

So, what's the basis for his Amazon comments?

Johnson told Yahoo Finance that he believes every company "gets about a 20-year run in retail." He pointed to department stores dominating retail in the 1960s and 1970s, and smaller stores, like The Gap, owning the 1980s and 1990s. He believes Amazon owned the 2000s and 2010s, leaving opportunities for Walmart and Target to come next.

Of course, it should be noted that Walmart and Target aren't newcomers to retail and have spent considerable time building massive big-box stores nationwide. And one could argue that while Amazon was dominating e-retail, Walmart and Target were dominating the brick-and-mortar.

Alas, no one has a crystal ball. But as Amazon continues to build out its online presence, the company is also taking aim at brick-and-mortar with Amazon Go cashierless stores and its Whole Foods acquisition. 

In other words, the fight may have only just begun.