I'm seeing publications expressing doubt we will reach herd immunity in the US because of vaccine-resistance.

This is actually not true in the big picture: We will reach herd immunity when almost everybody is either infected or vaccinated. When people are either infected or vaccinated that usually activates their T-cells against up to 52 different segments of the spike protein. This is why vaccinated people do not get seriously ill from the variants. It would require many many mutations to let a variant escape those T-cells. When the T-cells do react against a variant, the immune system makes antibodies that are specific toward that variant!

About a third of people in the US have yet to be infected or vaccinated. Around 100 million people. If those people get infected with a more lethal variant, many will die. It's their choice. Covid-19 will never die out completely, because it's in the wild animal population all over the world. Even if symptomatic infection becomes rare, it's still going to infect the unprotected, like rabies or hantavirus. The only way to defeat it is to get vaccinated.

The good news is that one completed vaccination (1 or 2) is likely to protect almost everybody from serious illness for decades. The other good news is we can probably come up with mRNA vaccines for ebola and the other related viruses.

We're flying electric helicopters on Mars yet you can't turn on your clothes dryer in Texas. That's because scientists are in charge of Mars, and Republicans are in charge of Texas.