That's what you think. 4 of the 7 specific coronaviruses that infect humans predate our ability to identify specific viruses. The were endemic already, they had crossed the globe sometime back in history. When and how they spread are things we can't ever truly know for certain, because there are inherent limitations studying history, but pandemics are the most obvious thing. For one of them, there is increasing evidence that
the pandemic of 1889-1890, one of the deadliest pandemics in human history and long believed to be caused by influenza, was actually caused by the coronavirus OC43, which is considered a common cold in the present.