But if we see here an apparently-sudden jump to a significantly different variant, does that make it less surprising that the original strain was novel?
1) Covid-19 was more dissimilar from previous coronaviruses than Omicron is from current ones.
2) There is a lot more covid-19 in the world now so rare occurrences are more common.
3) There was other evidence for the lab leak hypothesis. A cover up from China, a viral research lab in the city with the outbreak, etc...
And I still don't think Omicron is as different from original Sars-Cov-2 as Sars-Cov-2 was to known predecessors.
The number of scenarios where the new variant is engineered are vastly reduced, since it's less likely that this variant is a lab leak.
Other scenarios can still be within the realm of plausibility, but there are fewer of them.