The Canadian corporate tax rate is just 15%, and even Trudeau is pursuing aggressive neo-liberal policies. Canada would happily take our billionaires. (So would other English-speaking countries. Ireland, the U.K., and Canada have been the destination for dozens of corporate inversions over the last couple of decades.)
The U.S. is already the least economically free country in the Anglosphere: https://www.heritage.org/index/ranking. Do we really need to test how much we can squander our prosperity by being to the left of countries like France? https://www.dissentmagazine.org/article/emmanuel-macron-cont...
Especially when it's unnecessary? Elizabeth Warren's wealth tax, even on paper, will raise a fraction of the revenue that a VAT would. (Which Ireland, Canada, New Zealand, the U.K., and Australia all have, unlike the wealth tax.)
I don't know what economic freedom means, but the last time I checked, the US is doing just fine in the Capital department.
And a VAT is highly unpopular.