How did this many deaths become normal?

Following through some of the Center for Disease Control links on the page, there is a chart at https://www.cdc.gov/nchs/products/databriefs/db427.htm that displays how the leading causes of mortality in the U.S. changed between 2019 and 2020.

In short: most of the leading causes of mortality (including influenza in ninth position out of ten) were unaffected. COVID became the third leading cause behind heart disease and cancer and ahead of unintentional injuries.