The prediction that everyone in the U.K. is going to be exposed by Christmas does not seem remotely realistic. That is like two weeks from now. We don't yet know the reproductive rate or the incubation time.
In the United States, we only have a small number of cases that we know of. I'm sure that this will change.
We also don't know the case fatality rate, which so far seems very low.
This does not take into account mitigation efforts.
I am hearing that the symptoms tend to be different from regular COVID. It might more resemble a cold. Unvaccinated people have more severe disease with much worse headache.