Because the rate of spread is so high, that it will infect the entire county in a matter of weeks. Add to it, that we are not willing to do what it takes to slow the spread.

The cases are doubling every 2.5 days. Mathematically speaking it will take less than a month to infect everyone.

There will be a spike and then a rapid decrease as the virus runs out of susceptible hosts.

Take a look at the spike in South Africa. We will see the same in UK, and US and everwhere.