A million dead, mostly elderly, is not completely out of the realm of possibility, especially if we hit the high end of 150 million infections in the US. Statistically, 150 million infections would kill closer to 4 million.
Per https://www.thelancet.com/journals/laninf/article/PIIS1473-3... it seems that the basic reproduction number is over 2. Which means that herd immunity only sets in if under 1/3 of the population is vulnerable. Which means over 200 million Americans get it.
The alternatives are permanent lifestyle changes, or a successful eradication of the disease worldwide.