A third of the US population suffers from high blood pressure [1]. More than 100 million U.S. adults are now living with diabetes or prediabetes [2]. About 15 million Americans have cancer of some sort [3]. About 10 million people are immunocompromised or immunosuppressed [4]. So, you're not wrong! The high risk factor cohort is enormous, and the more risk factors you have, the higher your risk of death is (based on data coming out of Italy). A lot of folks are going to die from ailments they had and knew about, or ailments they had but didn't know about.

[1] https://www.cdc.gov/bloodpressure/facts.htm

[2] https://www.cdc.gov/media/releases/2017/p0718-diabetes-repor...

[3] https://seer.cancer.gov/statfacts/html/all.html

[4] https://www.google.com/search?q=americans+immunocompromised

That might be the case, but they are certainly not older than 80.

Point being is it is much of the danger can be attributed to being in poorer health to start with. JUST LIKE EVERY OTHER PATHOGEN.