FWIW, I do suspect cross-immunity will eventually explain a lot of mysteries of this virus, including why the Asia-Pacific region has been so lightly-hit compared to Europe and the Americas. So I do agree it's possible that weaker population immunity in more distant regions more than offsets less frequent spillover, and paradoxically makes them the more likely regions for an outbreak (although that's not what experts including Zhengli Shi had originally guessed).
But there's lots of other distant cities in China too, and none of them have virology institutes with the world's biggest collection of novel SARS-like viruses. So whatever your prior was for lab accident vs. natural, I do believe the location in Wuhan should significantly increase that. Certainly far from conclusive, but a possibility that requires serious investigation.