Actually I believe that a material amount of the population already has the virus. Which is good in a way because there haven't been mass hospitalization. Also, it will mean more folks are walking around who are already immune to the virus which is a good thing as well.
Not everyone who is infected with Covid 19 and survive will be immune from reinfection. I know you aren't exactly saying that everyone who gets it will be immune, but it's important to note that the jury is still out on reinfection because the data is so new and incomplete in that regard.