That would help explain how the virus got from the mine to Wuhan; it does not help explain how the virus mutated from a bat virus unable to infect humans to a virus that was extremely good at infecting humans with, so far, no intermediate stages identified.
Much of the problem with the zoonotic explanation is that no evidence of the process has been found. Was a third virus involved? We haven't identified it. Was a third host species involved? We haven't identified one. Were there any half-way variants that were slightly capable of infecting humans, and then mutated further to reach their final form? We haven't identified any. There was some initial speculation about the wet market, but that hasn't panned out. Pangolins were briefly considered as a possible intermediate host, but I think that's also been ruled out.
So if the lab collected the virus, flew it to Wuhan, stored it, and then accidentally leaked it in its original form, we still have no idea what happened next. It's a bat virus, so it infected a local Wuhan bat, and then what? And whatever the theory is, why have we been unable to find any evidence of it so far?
Assuming RaTG13 was indeed the source of COVID-19, the question of "how it got to Wuhan" is, I think, much less interesting than "how did it mutate into COVID-19" (and "why can't we find evidence of that process?"). And I think when people talk about "lab leak" versus "zoonotic", they're generally focused on the latter questions.
I generally agree with you, my guess is the virus was messed with and accidentally got out. However I don't feel comfortable ruling out alternative scenarios, such as:
1) The sample the lab received was from the 'third host' and not from a bat; e.g. a field researcher mailed the lab a slice of pangolin.
2) A guano miner or lab researcher received a massive viral dose and inadvertently became a one-man walking "GoF lab"
> Assuming RaTG13 was indeed the source of COVID-19, the question of "how it got to Wuhan" is, I think, much less interesting than "how did it mutate into COVID-19" (and "why can't we find evidence of that process?").
'Interesting' is subjective, but I think both questions are important. Particularly, the wisdom of locating a lab like this inside a city should probably be called into question. Whether the lab was doing GoF research on this virus prior to outbreak is certainly an important question; arguably the more important of the two. But unless we are dealing with 'zero-sum importance', that does not diminish the importance of figuring out why and how the virus was transported into a city.
> However I don't feel comfortable ruling out alternative scenarios
I haven't suggested we should, not do I think that would be wise. We're in the uncomfortable position of having effectively no evidence in favour of any theory of COVID-19s origin, so we're reduced to trying to imagine which bits of missing evidence are the least likely to have been missed.
It seems true that Wuhan is outside the flight range of the horseshoe bats living in the mine, and that a sample of RaTG13 was brought from the mine to the lab in Wuhan. If RaTG13 was a direct predecessor of COVID-19 (likely), and if the lab in Wuhan was the direct source of the initial infections in Wuhan (hard to estimate), then I think Occam's Razor suggests we have a good enough explanation for how RaTG13 got to Wuhan. It would be a remarkable coincidence if a sample of RaTG13
was in Wuhan to be studied, then RaTG13 independently mutated into an unknown COVID-19 precursor outside of Wuhan, then the precursor was separately brought to Wuhan to be studied, then the precursor leaked and became COVID-19!
...but as ever with this mess, I don't know of a reason we could rule it out. At most we can try and estimate the odds of the lab having a closer precursor than RaTG13 but not realising or, if they realised it, not admitting it, but I'm not sure how to even start evaluating that scenario, so...
and the WHO researchers themselves engage in (and fund) the same type of experiments as the Wuhan lab (and the Wuhan lab itself), and so had very little incentive to investigate or implicate themselves either...
Much of the problem with the zoonotic explanation is that no evidence of the process has been found. Was a third virus involved? We haven't identified it. Was a third host species involved? We haven't identified one. Were there any half-way variants that were slightly capable of infecting humans, and then mutated further to reach their final form? We haven't identified any. There was some initial speculation about the wet market, but that hasn't panned out. Pangolins were briefly considered as a possible intermediate host, but I think that's also been ruled out.
So if the lab collected the virus, flew it to Wuhan, stored it, and then accidentally leaked it in its original form, we still have no idea what happened next. It's a bat virus, so it infected a local Wuhan bat, and then what? And whatever the theory is, why have we been unable to find any evidence of it so far?
Assuming RaTG13 was indeed the source of COVID-19, the question of "how it got to Wuhan" is, I think, much less interesting than "how did it mutate into COVID-19" (and "why can't we find evidence of that process?"). And I think when people talk about "lab leak" versus "zoonotic", they're generally focused on the latter questions.