If someone can figure out how to keep out the homeless, migrants and criminals, they wouldn't need a tech company, they could become billionaires just building cities.
Mmm anywhere that doesn't have a military defending it is pretty dangerous place to invest as well. I think the US is probably still the safest / most realistic.
@lain@cjd It's not exactly unknown, but as you say, shaky environment. Even though ZEDEs got constitutional protection for 50 years, the current government is already talking about violating the constitution and taking away their rights.