Why Covid-19 is no "great plague"

Horrific plagues of the past like the Black Death and the Spanish Flu have scarred the collective memory. For quite a while there has been a feeling that we were "overdue" another "Great Plague". And many people thought Covid-19 was the one.
But this idea is completely flawed. It ignores the massive steps we have taken in the developed world to improve public sanitation, nutrition and living conditions.