This has been stated several times, but I guess here it goes again. When a disease has a high prevalence, the seemingly small-ish percentage of people who will suffer a severe outcome becomes increasingly large in raw numbers.
Let's give a conservative estimate of the fatality rate from COVID-19 (not even considering the extensive morbidity associated with the condition) at 1-3%. And now lets consider a situation in which we did nothing to prevent the spread of the disease, it became endemic, and affects virtually the entire population of the US (as chicken pox, measles, mumps and rubella did before vaccination). In this situation, with the US population of 331 million, anywhere from 3.31 to almost 10 million people would die in this country alone. That's 3-10 million EXCESS deaths, at a minimum, and there would probably be many more indirect deaths because this sheer number of sick individuals would cause the health care system to collapse. Even if only 10% of the population catches the disease, this would still result in an excess of 331,000 to 1 million deaths. We're well on our way to hitting the lower estimate already.
For comparison, the two most deadly wars for the US were WWII and the Civil War, with 291K and 218K combat deaths, respectively. And because people keep mentioning the flu, the most deadly year for influenza in recent years in the US killed about 16,000. For COVID-19 deaths, in less than a year, at 231K, we've long surpassed the Civil War body count, but we're closing in on our total in 3+ years of fighting in WWII.