Historically - and we are talking all the way back to Biblical times - epidemics do not hit populations randomly. They CAN infect any susceptible, but the susceptibles they DO infect with greatest frequency are those generally at highest risk due to geographic or cultural factors. Once those individuals have had the illness and recovered (or even died) the population as a whole is at LESS risk because those people have now been eliminated (one way or another) from the pool of susceptibles.

If death rate for those under 60 and not occupationally exposed is less than 0.4% (and it is) then every thousand people who get the illness wind up leaving behind 996 who are at least relatively immune, and given the number of totally asymptomatic cases that never get diagnosed (The USS Theodore Roosevelt had out of a crew of 5000 about 1000 infected, but 3000 with antibodies, most totally asymptomatic and with only one (1) death)even higher numbers than that who are now resistant or immune.

Herd immunity happens. It does not require a fixed percentage, ANY number of immunes out there helps to slow the epidemic to some degree. Right now coronavirus has taken out the most susceptible and left behind both the less susceptible and the once most susceptible but now immunes. The longer this goes on the less effective the spread of the organism will be. Similarly, the strains of the coronavirus that are the most susceptible at spreading will be the less lethal strains. That’s just how epidemics always have worked and there is no indication this one will work any differently. Time itself is on our side.