Even in the beginning it's not exponential. It's a very simplistic model used to give an idea, maybe to teach high-school students about how it might look like.

Even in the beginning it's not exponential. It's a very simplistic model used to give an idea, maybe to teach high-school students about how it might look like. It's not exactly a logistic model either, although that's clearly a better approximation. One critical aspect is that humans act and react. They cluster. They're not random gas molecules. See this article for a better explanation: https://www.zdnet.com/article/graph-theory-suggests-covid-19-might-be-a-small-world-after-all/ https://www.zdnet.com/article/graph-theory-suggests-covid-19...