Macau has returned to growth over the past year, but that's also coincided with the Parisian opening and new resorts from Melco Resorts (NASDAQ: MLCO), Wynn Resorts (NASDAQ: WYNN), and most recently MGM Resorts (NYSE: MGM). That's diluted the market in Macau -- and even as the whole market grows, Las Vegas Sands is losing market share to rivals.