Maybe these economies shall try to attract the wealthy before trying to tax them ... Or is that so that because of past fiscal policies, the wealthy are gone and are now missing out to the economy? :-)
The reality is that many (other) countries understand this and attract these wealthy people who contribute to their own economy - because wealthy people are more than people with a large bank account, it's usually entrepreneurs who will hire local workforce for their business, buy real estate, etc.
If one knows Brazil and especially Spain, the other reality is that this initiative is certainly driven by a socialist-populist agenda, nothing to see here.
Either way, this initiative is just a show, and sure to fail for many reasons.