Wall Street, however, has never placed much value in Mr. Bezos’ emphasis on customers. What he has viewed as money well spent — building customer loyalty — many investors saw as giving away money that should have gone to the bottom line. “What makes their core business so compelling is that they are focused on everything the customer wants,” said Scott W. Devitt, who follows Amazon for Stifel Nicolaus & Company. “When you act in that manner many times Wall Street doesn’t appreciate it.” What Wall Street wanted from Amazon is what it always wants: short-term results. That is precisely what Dell tried to give investors when it scrimped on customer service and what eBay did when it heaped new costs on its most dedicated sellers. Eventually, these short-sighted decisions caught up with both companies.

But Mr. Bezos refused to give in. “He was spending his time on long-term value creation,” Mr. Miller said.