You are making an apples to oranges comparison. Fatality rate in the context I am speaking of is the percent of people who die out of those who contract the virus, not the overall percent of the global population who dies. For spanish influenza, that number was 10% to 20%. For coronavirus, it stands at about 2-3% currently.

In other words, spanish influenza killed 10-20% of those infected which equated to 2-3% of the entire world population (infection rate was around 33%, not fatality rate). Coronavirus appears to kill 2-3% of those infected (though that's a preliminary number) but what the overall effect on world population will be will depend on infection rate.