These fatality rate estimates assume top quality medical care. And this crisis is quite simply not "here to stay"; decisive measures can definitely "flatten the curve" and perhaps even lower R0 so much that the virus stops spreading altogether, and cases start dropping towards zero.

Assuming no medical treatment because the medical system is already full? I doubt it.

Actually many of the statements from your post were absolutely false.

"Fatality rate for 50 and below is a paltry 0.2%"

For a typical seasonal influenza, the fatality rate for that age bracket is around 0.01%, so this is much more lethal to those people than the flue.

https://www.businessinsider.com/coronavirus-compared-to-flu-...