The law changes dramatically every time there is a new government. The bitcoin protocol stays the same.
That is not true. The bitcoin protocol can change and did change. If you fire up the original wallet it won't sync.
Small incremental changes based on almost universal consensus, yes. Not the same as political change. The big block size guys failed to make a big politically charged change. Bitcoin has shown its resistance to political change very clearly.
With a nation state you instead rely on the intrinsic properties of the law. No ifs or buts.