Accessibility of global wealth seems more important. In the age of sail, I'm sure one could have stashed gold in some backwater city, which would have hidden i

Accessibility of global wealth seems more important. In the age of sail, I'm sure one could have stashed gold in some backwater city, which would have hidden it very effectively from any government. But then you couldn't use it. The international banking & legal systems now enable those with means to both keep wealth away from governments while still maintaining access to it for practical purposes.