It's plausible, and could be proven very easily that this happened. Presumably, some progenitor strain is out there, spreading more slowly and making less of a

It's plausible, and could be proven very easily that this happened. Presumably, some progenitor strain is out there, spreading more slowly and making less of a mess. Eventually, a SARS-CoV-2 screen will turn it up and we'll sequence it. Then we will see a strain that's diverged from all other sequences in the phylogenetic tree, with a common ancestor back further than ~1ya.