Respectfully, I won’t speak for others, but I know no one in good conscious is wish casting any terrible figures.
Let’s do some back of envelope math:
US has population of ~330M
Using H1N1 as a baseline, 1 in 6 US citizens contracted that novel virus. And that figure is potentially low as H1N1 was positively affected by the availability of a vaccine in the 2nd wave and first wave was mitigated by a late start in Spring of 2009 (flu transmission being seasonally affected and availability of antivirals approved for flu treatment).
CDC’s current projected case fatality rate for COVID19 is 0.9%*. Taking a 1 in 6 infection rate, that is 55M. Applying 0.9% case fatality rate, that equates to 495,000 deaths.
While social distancing slows transmission, in absence of a vaccine/effective treatment, does not stop the virus. This virus shows troubling transmission capabilities by asymptomatic carriers and any waning of new cases could just as quickly loosen existing containment measures prematurely.
Will medical treatment breakthroughs happen, I pray to god yes, but there is plenty of head room for significant headcount losses in addition to the fiscal catastrophe.
While the above are over-simplications, it shows the frameworks for some of the more dire predictions/outcomes
Unknowns:
- US fatality rate; this is the most fluid and obviously hope for the lowest figure possible
- Is this specific Coronavirus transmission affected seasonally
- Re-infection; other coronavirus variants have resulted in antibodies have shown to only provide immunity for as low as 4 months, are recovered populations healed or potential for re-transmission at a future date
- Compounding effects of overwhelming an overburdened medical system
*Case Fatality Rate:
"We estimated the case-fatality risk for 2019 novel coronavirus disease cases in China (3.5%); China, excluding Hubei Province (0.8%); 82 countries, territories, and areas (4.2%); and on a cruise ship (0.6%). Lower estimates might be closest to the true value, but a broad range of 0.25%–3.0% probably should be considered."