https://www.npr.org/sections/goatsandsoda/2020/04/23/8417296...
So I would upgrade that quite a bit from "moderate-low." (One of the researchers in this NPR article seems to rate it as an obvious suspect, so I'd call that "high likelihood.")
"AIDS was first clinically reported on June 5, 1981, with five cases in the United States"
"Both HIV-1 and HIV-2 are believed to have originated in non-human primates in West-central Africa and were transferred to humans in the early 20th century."
If HIV, a relatively less infectious virus, can make its way across the Atlantic Ocean to land on America shores, I wouldn't be surprised SARS-CoV-2 could do the same. Another explanation could be that SARS-CoV-2 is a lot more common than we think --- many people might have caught it before but it didn't manage to spread, but this time the virus just hit the jackpot.
It also presents some reasons why bat viruses on their own were unlikely to become as contagious as COVID, citing the example of RaTG13's discovery.
So the "zoonotic transfer from bats" theory requires an extraordinary new strain (possible!) to travel a thousand miles before spreading enough to be detected.
If I am wrong or misinformed, I would like to know it. The submission is an excellent article. I have no dog in this fight but it did shift the needle of uncertainty for me, particularly when I learned about prior leaks and the suppression of investigations in China. It’s a long article but worth the read.