What are the reasons for low reliability of driver of high power LED light and other LED lights of LED industry

Although luminous efficiency of LED light especially high power LED light including high power LED flood light is higher, but just a small part of electricity flowing through the LED can be radiated in the form of visible light energy, most of the remaining energy is consumed in the form of heat in the LED, the LED light source particularly high power LED flood light and other power LED light has serious fever. there are following reasons for low reliability of   driver of  high power...