Mathematically this makes no sense. If we all had it already it wouldn’t have an R0 of 2-3. And, if you model the infection rate, even with it being highly exponential, it still takes many many months to spread everywhere because of a) the ~4 day delay from infection of a person to their infectious-ness b) it being a phenomena that must be seeded in each local community and c) applying the prior to the exponential function.

I won’t bother re-creating the epidemiological studies as professionals have much better simulations than I could offer.

I will urge you to read up on the models before assuming this thing is “already everywhere” which also implies it won’t grow exponentially.