Why aren't adult diapers marketed toward everyone with a busy lifestyle

If you eat or drink something it is going to come out.  Simple logic right?  If you are sick it is probably going to come out faster, right?  If you are on medication it might come out more often.  Don't wait until the last explosive second, when it turns into a dire emergency.   

I want to add to the list of certainties in life:

• death
• taxes
• bowel movements
• urination