The numbers were pretty clear. To get to herd immunity WITHOUT a vaccine you either have to permanently modify pretty much everyone’s behavior (fat chance of that!) or you have to get to something like (low-balling) 65% who have recovered from the infection. There are 330 million in the US, so about 215 million people have to be infected. The death rate once you’re infected is (lets just low-ball this too) 0.8%, so 1,720,000 people will have to die to get there without the vaccine. That would be 1.4 million more deaths. The number we’ve already seen, plus FOUR times that number (more or less).
And that’s the (approximate) truth.