Investors love the brand, but the real story lies in whether management can turn nostalgia into sustainable profits.Krispy Kreme (DNUT +4.08%) has long been a brand that evokes nostalgia. For generations of Americans, that glowing "Hot Now" sign meant one thing: A fresh, warm, glazed doughnut -- and often, a moment of indulgent joy.But while the brand's emotional pull remains strong, its business performance has been far less consistent.Today, Krispy Kreme finds itself at a critical crossroads. Once again, ...