Roiled by economic tumult, waves of layoffs that will slash some 21,000 workers, and a costly investment in the virtual reality "metaverse" that shows no immediate signs of paying off, many inside Meta say Zuckerberg has lost his vision....Meta's core product, Facebook, is battling TikTok for users and marketers. Economic forces have cut into its advertising business. The company lags on generative artificial intelligence, which is quickly revolutionizing the tech industry.