Americans love their Starbucks SBUX pumpkin-spice lattes. But as popular as the drink may be, can it alone reverse the fortunes of the financially challenged coffee chain?That’s the question some might be asking in light of recent developments. The popular fall-themed beverage has returned — for the 21st year — to the chain’s menu as of Thursday. But more important: Starbucks has a new CEO, Brian Niccol, coming aboard starting Sept. 9, an announcement that’s been greeted as a positive move by Wall Street fo ...