I'm aware of the Neil Ferguson model. He is not the sole reason why everyone across the globe are taking this seriously. The statistics alone prove this virus has a higher than normal fatality rate among infected. Most seasonal flu only have a .3% virus at the very least, this is the first virus in the US in over 100 years that has a fatality rate of 1% or higher. That means at least one in hundred infected will die. If every person were infected with Covid-19 in the United States, that is potentially 30 million deaths.
Ferguson's model, though highly questionable, only claims less than a tenth of that will die. Likely calculating those at risk such as the elderly and those with diabetes. 47 million make up the elderly in the US and 1.2 million make up those with type-1 diabetes. It is far more likely his model takes this into account to allow people to plan accordingly. Even if you dismiss the Ferguson model, which I think you should as there are far too many variables to hold it reliable, you can at least follow the fatality rate as it fluctuates to determine how much of a risk there is in being exposed to the virus as well exposing other to it.
At this time, we do not know the final fatality rate so it is not recommended to factor population into it as the number of people could increase, and allow the fatality rate to hopefully drop or unfortunately increase.