Good point. I've probably been lucky. I did have an opener that went out after ~10 years. It was on a double wide wooden door and the output countershaft bushings/bearings wore out. It turned out I was able to get a replacement assembly with the output sprocket/shaft/bearings for ~$35. That door was pretty heavy and went through more cycles being operated for two vehicles. The one that lasted 16 years was on a much lighter single-wide steel door. I'm sure it's more related to the weight and number of cycles than years.

Edit: Just realized the the play on words in my last sentence above, "number of cycles". In this case the number of cycles is the number of open/close operations of the door. Number of bicycles would relate to the value of operating the door to reduce the probability of theft.