NVIDIA Corp (NASDAQ:NVDA) has been a Wall Street favorite for its consistent earnings beat, but a prominent investor has raised concerns about the sustainability of its market share. What Happened: Despite Nvidia’s recent earnings beat, Rob Arnott, the founder of Research Affiliates, is skeptical about the company’s long-term prospects. “It seems bubbly,” he told CNBC’s Squawk Box on Thursday. “The price-to-sales ratio is astronomical, and it’s astronomical because their profit margins are absolutely ginormous.” Arnott pointed out that Nvidia’s current success is largely due to its high-profit…