I really wonder if it was the wind that did it?? They have several of these near Laramie Wyo and 40mph is barely considered wind there...
Those blades are under a lot of stress. If you make them strong, they tend to be heavier and less efficient. If you make them light weight, they’re more efficient but will tend to be weaker. Of course, you can use high tech materials like carbon fiber, but manufacturing something that large from CF is tricky. Bird strikes on the blades can cause damage that might not be noticed for a while. Still, the wind turbine should be able to turn away from the wind and feather itself if the wind speed is too high.