The evidence of the SARS-CoV-1 spillover is still around. You can still find the precursor virus in specific bat populations. There is also an evidence trail for the spillover of MERS. The same type of evidence trail does not exist for SARS-CoV-2. We do not know the original host animal. We still have not found the precursor virus(s).

I know that the absence of evidence does not prove anything, but in this case the absence of evidence is conspicuous. Either it wasn't a spillover event, or our entire understanding of spillover events is incorrect. Occam's razor applies here. We have hunted extensively for the origins SARS-CoV-2, in every way allowed by the Chinese government, and still have not found conclusive evidence of a spillover. I find the lab leak hypothesis to be far more plausible than a complete misunderstanding of how spillover events work in the 21st century.