We do see it though. But usually they hide the income overseas because that's more straightforward or cheaper or whatever. However there are several small island countries that are known for hosting ultra wealthy expats on very favorable terms. This isn't some hypothetical.

In the business world how many companies are just coincidentally booking all their revenue in Ireland?

I'm really not clear what point you're trying to argue here. Someone upthread suggested that a sense of community would prevent the disproportionately wealthy from relocating to nearby states to avoid higher taxes. I call bullshit, dependent on the size of the relative tax gap. They don't even have to sell their house, just purchase a second one and reside there more of the year.