So why is this on slashdot exactly? This site is supposed to be about the tech itself, not the financial problems of the people behind it.
Treating this like "Shuttleworth's problem" is losing sight of the big picture. The SA government is desperate to prevent money leaving the country, because if it was easy to get out, a significant chunk of the population would (SA, particularly in the large cities, is not a fun place to live). They may have eliminated the apartheid-era controls, but they've introduced far stricter ones to prevent capital flight from the country. Shuttleworth's case is just one of the more visible ones, there are huge numbers of people who would leave if they could get their money out.
I think this is part of a more general problem. You see it more in lousy countries like South Africa, but the same thing really happens to a lesser degree everywhere.
In every country lots of people are born and die every year, and many people come and go. Those who are born tend to have abilities that fall onto various bell curves, generally reflective of the people who are already there, and the same is true of those who die. Those who come and go are not distributed in the same way. Those with a lot of talent/resources are much more mobile than those who lack these. If the country is a desirable place to live for those with the means to move, then there will be a net flow of these populations into the country. If the country is undesirable for the mobile to live in, then they will tend to leave.
So, if a country has lousy conditions or taxes mobile populations higher than other countries, then it will tend to lose these mobile populations. The problem is that these are also the people who are most able to pay taxes. People who are unable to earn much of an income or who are needy (disabled, etc) tend to stick around. That creates a downward spiral as those who are able to work leave, and those who are unable to work accumulate, and thus increase the demands on those who remain and still pay taxes.
The usual solution to this is to make it more difficult for people to leave on their own. The only other solutions I'm aware of basically amount to begging, or just neglecting those in need so that those who are well off don't have to pay for them and thus don't have as much incentive to leave.