A special perk for Costco Wholesale's highest tier of cardholders has some members in an uproar -- but it's put smiles on the faces of management and investors.For the last three years, the evolution of artificial intelligence (AI) has captivated the attention of Wall Street and investors. In Sizing the Prize, the analysts at PwC pegged the potential global impact of AI at $15.7 trillion by the turn of the decade. Numbers this large are bound to garner the attention of investors.But this sky-high estimate f ...