They don't owe any taxes if they keep the money outside the country.
People tend to think of taxes like "skimming" off the top, and like some kind of inevitable thing that doesn't affect your decisions. But that is the wrong way to think about it: when taxes are high enough to have a significant impact, they do affect taxpayer decisions.
You seem to be saying that they should keep making decisions as if there were no taxes, and then pay high taxes because of those decisions. But that's completely unrealistic.
When taxes are higher than a trivial amount, the correct way to think about them is as policy that will have lots of effects; some obvious and some not obvious.