> anyone resident in the US
Yes, I'm well aware of that. I moved to the U.S. in 2007, and I'm not a citizen or a permanent resident yet (and not that close getting permanent residency either). Not because I don't want to become a US citizen, but because US immigration laws make it incredibly difficult to gain permanent residency if you're not family-sponsored and qualify for refuge/asylum. My presence in the US, per the IRS' Substantial Presence Test[1], makes me a "US person" and subjects me to the related taxes. I use the word "American"[2] in the sense defined by Jose Antonio Vargas[3]. He's written a great book[4] on the topic.
> the SEC prohibits – among other things – foreign financial institutions that are not registered and regulated in the US abroad from soliciting US residents as clients
This is a good thing, and this makes perfect sense. The SEC exists to protect US investors. If an unregulated nefarious company solicited US investors, that would expose them to potentially huge danger. There are enough bad-faith and Ponzi investment schemes cropping up, it's best to not expose Americans to soliciting from investment firms all around the word.
But -- as far as I'm aware -- nowhere does federal law or regulations (incl. SEC rules) state that a US person can't open a brokerage account abroad. Sure, a foreign brokerage can't advertise to you nor solicit you, but there's nothing preventing you from doing your research, and finding a brokerage abroad you like, and applying to open an account with them. (Of course, it'll depend on that country's rules and whether they allow non-citizen non-resident person to open brokerage accounts in their country, but in general, one could say a country loses nothing by receiving foreign direct investment, so would likely welcome it.)
> They didn't do anything other than be born, so you're basically rewarding them with a privileged lifestyle ...
Let's clarify who gets the proceeds from your hypothetical 90% tax. The citizens of the X country? I want to ask a rhetorical question at this point: why should the citizen of the X country be rewarded over another country? Because they were born there or have ancestry to the people who inhabited that land a long time ago? As per your argument, they didn't do anything to deserve it. Other than being born on X piece of soil. I've paid hundreds of thousands of dollars in taxes. The US has such horrid immigration laws that it's almost impossible for anyone to obtain permanent residency in this country outside family/DV/reugee+asylee routes. The fact that I've been here for over a decade legally, and have paid hundreds of thousands of dollars in taxes -- counts for nothing/nada/zilch under US immigration law. My freedom to live here could be stripped away easily if I lost my job. I'm years away from citizenship. So here's my question: wouldn't the right thing to do be to distribute all of the revenue equally to the whole world? Is that fine?
> hey earned it, they should benefit from it.
What if they don't want to benefit from it, but rather want someone else to benefit from it? Why is that not okay? Spending money on oneself vs spending it on someone else -- where's the distinction? Perhaps they get great joy in giving the money to others. That's their choice. By the way, the only distinction between the two kinds of money transfers is that one's a donation/gift, while the other is a transaction involving the exchange of services/goods. What you want is to effectively ban gifts and donations. It seems like in your ideal world, all people (are forced to) engage in purely transactional relationships, and charity is non-existent/banned.
In summary, what I can say is: all of your ideas and arguments are truly shallow, poorly thought-out, logically inconsistent, and incoherent. While leaning heavily towards communistic tendencies, and an utter destruction of personal freedom / individual liberty.
[1] https://www.irs.gov/individuals/international-taxpayers/subs...
[2] https://defineamerican.com/
[3] https://en.wikipedia.org/wiki/Jose_Antonio_Vargas
[4] https://www.amazon.com/gp/product/B0776TSKBJ/