If a politically stable nation with a good international reputation were to guarantee government respect for data privacy for data centres housed on its soil and run by its companies, that nation could become the Swiss bankers of data. Rolling your own "digital sovereignty" is not going to be cheap for most nations, and many other nations simply won't be trusted by anyone, least of all their own citizens. It's a bit…
You could take your analogy further, and consider why the Swiss banking isn’t so opaque anymore. Hint: people who did really inhuman things used that system to store their profits, and the Swiss society, developed and stable as it is, decided that they don’t want to bear the moral cost of it anymore.
And of course the external pressure to loosen banking secrecy laws has been huge, particularly from the US e.g. https://en.wikipedia.org/wiki/UBS_tax_evasion_controversies