The owner of a Bitcoin node could rewrite the history of their chain, too. (After all, it's just a file on a hard disk.) This would, however, make their node i

The owner of a Bitcoin node could rewrite the history of their chain, too. (After all, it's just a file on a hard disk.) This would, however, make their node incompatible with everyone else's, in exactly the same way that rewriting the history of a Git repository makes that repository not able to automatically pull from or push to any other non-rewritten repos. You seem to be thinking of 'git' as a thing which gets stored on GitHub, but it's entirely possible to run a repository with no central copy, based only on consensus. (I've actually done this--in an area without an internet connection, we spent a day coding and passing around copies on flash drives and merging until everyone had the same code. I don't recommend doing this on a regular basis, but there's no technical differences preventing it.)