There’s a ton of intricacies to it though, for example if you live in Canada you can’t invest in one of the two retirement accounts without paying some pretty hefty fees. Primary residence are only excluded for a relatively small amount (might be enough if you live in a small town, forget it if you live in a major metropolitan area past a small one bedroom condo), and the division with a partner isn’t 50/50 like it is in Canada so your Canadian partner potentially looses a ton of money. Increases the cost of accountants and personal finance advisors by like three folds. Etc, etc…

I get that trying to get rich people to not use tax heavens is good. But this affects regular people who haven’t lived in the country for years, decades, as well as their non American families.

I know this first hand, and second hand, as my immediate and extended family is all sort of cross border intertwined. It’s a real pain in the ass.