The restaurant industry can expect some troubled times ahead. After a prolonged period of growth, fueled by Wall Street, experts say the market is now oversaturated with casual, fast-food and chain restaurants, the New York Times reports. After the dot-com bust, many investors turned away from Silicon Valley and looked toward the hospitality sector for more reliable — although smaller — returns. The New York Times reported that Wall Street “poured billions into the restaurant industry.” In recent years, the number of restaurants in the U.S. — currently estimated at about 620,000 — has grown at twice the rate of the population. It’s true that customers are faced with busy lifestyles and continue to spend a large portion of their food budget at restaurants. But that dollar amount is now being spread across an ever-increasing number of establishments, so profits are divided into smaller and smaller pieces. Changes in single-store sales over time are down to the lowest they’ve been…