A customer exits a Walgreens Boots Alliance Inc. store in Elmwood Park, Illinois. Photographer: Christopher Dilts/Bloomberg

As the middle continues to collapse—and many well established retailers struggle to move from boring to remarkable—brands must continually seek new ways to become unique, more intensely relevant and truly memorable. One strategy that seems to be picking up steam involves so-called digitally native brands creating alliances with much larger legacy retail companies. Earlier this month, as just one example, Walgreen’s announced a partnership with fast growing online beauty brand Birchbox. An initial pilot will feature a Birchbox offering in 11 Walgreen stores.

The Walgreen’s and Birchbox deal is only the most recent of many business marriages forged in recent years. Target has been especially forward leaning, expanding its assortments via industry disruptors Casper (mattresses), Quip (ultrasonic toothbrushes) and Harry’s (razorblades), among more than a half dozen others. Nordstrom has been active as well, having added (and invested in) Bonobo’s (menswear) way back in 2012. More recently, it has augmented its offering with Reformation (women’s clothing) and Allbirds (shoes). Earlier this year Macy’s invested in and expanded the number of stores featuring b8ta’s store-within-a store concept and Blue Apron began testing distribution through Costco.

I first came to understand the potential power of these alliances when I worked on Sears’ 2002 acquisition of Lands’ End. While the roll-out of Lands’ End products at Sears was horribly botched (and hindered by Sears’ bigger problems), the strategic motivations are easy to grasp. For Sears, struggling to offer powerfully customer relevant brands that weren’t widely distributed at competing retailers, Land’s End held the promise of providing product differentiation, an image…