text:  This is Viewpoints Explained. I'm Ebony McMorris. Go back a decade and frozen yogurt chains were popping up left and right. People couldn't get enough of the self-serve setup, low-fat options, and countless toppings. Chains like Forever Yogurt, Menchies, Red Mango, and more all seemed to be capitalizing on the craze. But in recent years, many of these fro-yo locations have shuttered. What happened?