Your question: Why do people die of asthma
My humble answer: For most people, I'd guestimate about 90-99% percent, asthma is more annoying than something that kills. Asthma is a disease that's reversible with either time or medicine, and can inflict poeple of any age at any time. You don't even need to have the asthma gene to get it. Usually asthma doesn't become life threatening until it's mixed with other disease conditions, such as pneumonia, influenza, heart failure, kidney failure, etc. Age can also be a factor here as well. But, from my knowledge, asthma in and of itself has a very low death rate (less than 1% of asthmatics). Smoking can also complicate asthma, as well as second hand smoke. You haven't provided this information, so I'm just rattling off some possibilities here.