We don’t have enough people vaccinated to see major and obvious impacts yet. Israel does. They went from an average of nearly 10,000 cases per day and 100 deaths per day down to 52 cases per day and 1 death.
So clearly something is working.
I’d argue that:
1) Nowhere I know of has it been true that naturally acquired herd immunity has yet been enough to prevent recurring waves of COVID-19. Some people thought India might have achieved a measure of herd immunity, heck, I even gave that idea some credence, but it was obviously incorrect.
2) Human behavior is one of the key factors in infectious disease spread. The easing of mandates aside, behavior here in the US is, so far as I can personally observe, trending strongly in the direction of higher transmission. Mobility, gatherings, mitigation fatigue, and more, are all on the increase, and, really, must be. A society such as ours just can’t be shut down for so long and survive. It has already taken great damage. Instinct tells most to resume mostly normal lives in the face of an apparent decreasing risk, and at present a sort of balance seems to be in place.
3) Variants may be a factor. I suppose this needs either in depth discussion, or just leave it as stated. ;-)
4) There may be a continuing sort of “floor” of COVID-19 injured / complication injured people finally dying off. I have anecdotally seen this a lot: An elderly person in pretty good health takes a hit, so to speak, from a disease or physical injury, the doctors pull them through, but “diminished”, and then they die within the year. This is very common after hip fractures in elderly folks, for example. The injury would not seem to be fatal, but, given some time, the repercussions are.
5) Have I missed something or things? Almost certainly.
Then I take another look at India’s recent incredible acceleration of cases compared to their 1st year of COVID-19, and taking the above into account, perhaps all things considered, like the British at Malta trying to hold off the Germans and Italians, maybe hanging in there or only a slight improvement in the situation actually is doing quite well.