You are mistaken.
A single person can infect more than one.
If that person has the flu and travels, it
could be hundreds.
I’m not mistaken, I am describing a model that is commonly used to illustrate how contagious a disease is.
It is a model, used to convey information on how fast a disease “might” spread, not how many will be infected by a single person in reality.
It is a simple fact that if you put a person infected with measles on a plane full of un-immunized people, you are going to have a far, FAR different spread of a disease in an incredibly short period of time, than you would if you put someone on Ebola on a plane full of people.
That is what R0 is meant to convey.