[Buttons12]

The way I heard it, the flu hit (and killed) young healthy adults worse than any other category. Something to do with immune system overreaction.
But war and disease certainly had its consequences.
So did motion pictures. Sudden wealth in Hollywood led to excesses onscreen and off, and the films affected fashion and morals.
Also, war got women out of the house and into the work force.

[hanamizu]

A good vid explaining the ‘Spanish Flu’, including why it was called the Spanish Flu can be found here:

https://www.youtube.com/watch?v=sE0-WWqhFls&t=124s&frags=pl%2Cwn

Young and healthy were particularly hard hit, partially because older adults had been exposed/survived a related strain years earlier.

[GOPJ]

The Spanish flu pandemic of 1918, the deadliest in history, infected an estimated 500 million people worldwide—about one-third of the planet's population—and killed an estimated 20 million to 50 million victims, including some 675,000 Americans.Oct 12, 2010 wiki

You're right about the groups hardest hit by the disease - it was young adults... I remember from family stories a long time ago about the concentration of wealth which fueled much of the roaring twenties. Of course those family members have been dead for decades. I should have researched this a little before making a comment.