The other conclusion from the threads was that Bitcoin is ultimately protected by... the US federal government. Any actor, be it private or national, would have the USA to contend with if it were to try something like this. Indeed, it is undoubtedly the threat of the US government's reprisals that probably keeps a major entity from attacking Bitcoin. (Kind of ironic, given all of the anti-government rhetoric coming from some of the Bitcoin community).
This is a very interesting point to discuss. I admittedly don't know much about the topic, but I did read this blog post by Conklin et al.,
https://sites.duke.edu/thefinregblog/2022/12/28/legal-liability-of-a-51-goldfinger-cryptocurrency-attack, as part of my research, which concludes that a 51% attack will be hard to prosecute in reality.
Its argument in particular about why the Computer Fraud and Abuse Act would be difficult for a prosecutor to use is quite interesting.