How does one actually die of influenza?

And how come there were four generations in the developed world who thought this unthinkable?

Usually it is as a result of several things.
It is quite common for the person who dies to be asthmatic, and so when their airways are partically blocked during the flu it triggers an asthma attack.
There are also problems with weak immune system, and other conflicting diseases, but these are not really healthy people.

The other main complication comes from treating the fever by wrapping the person in more and more blankets until they overheat so much they die. This is much more common in babies and young children who cannot control their body temperature as well though.

Comments

Good point about the over-heating. When I was a kid parents thought that sweating out a fever was a good idea. Maybe some still think that.