I'm a former fitness instructor and I totally agree with you. These high intensity workouts are great for losing weight but most people find them to hard and not much fun. I feel people are more likely to stick to a basic aerobic class or a 30 min walk. People are also less likely to injure themselves through using poor form by trying to rush or push themselves to far. Many are just not fit or healthy enough for these kinds of exercises. These exercises can be dangerous for those with health conditions, over weight and obesity.