The two-company thing came about when the US gov decided to interfere in the market and treat it as a utility, resulting on zero competition, low profit margins and little incentive for innovation. This allowed foreign companies to profitably enter the subcontracting production market. Where we are today.

Most of the time influenza is a minor inconvenience, unless your immune system is compromised through age or disease. Then flu can be lethal.

Also, it is good to remember that the influenza ("Spanish Flu", look it up) epidemic at the end of WWI killed more soldiers than the war killed and it also killed millions of civilians world-wide. Epidemiological studies revealed that it killed a disproportionate number of young men and women--not the typical pattern of flu.

There is no reason to suppose that it cannot happen again.