Premium brands competing over the growing purchasing power of Gen Z and millennial consumers could have a lot to gain. Gen Z and millennials wield nearly $165 billion in purchasing power, and their spending is expected to boom as the two cohorts inherit an estimated $60 trillion of wealth by 2050, according to research by TD Cowen. "As these cohorts, who have grown up in the digital age, grow older and experience rising income, along with the potential for substantial wealth inheritance," the TD Cowen analysts wrote, "consumption patterns of these cohorts could lead to profound shifts in the retail,…