As the Panama Papers and many other high profile leaks show, these rich folk are not paying their share in taxes. Its a huge scam where the middle class has to bear the tax burden.
The problem is that the truly rich won't have an issue with these changes, it will be well-off middle class that is considered rich in South Africa.
In regards to middle class:
Household income
According to the 2020 EU-SILC (European Community Statistics on Income and Living Conditions), Austrian private households have a median household income of €39 549 a year. 10% of households have less than €15 735, and 10% have more than €81 771 per annum at their disposal.
www.statistik.at
Note that is yearly income and is probably a bit wrong as many super rich don't really have an income (everything is already paid off/done via company/whatever other loophole).
Contrast that with South Africa:
According to the research data, among South Africa’s adult population of approximately 35.4 million people, the average wealth held in a personal capacity is
R326,000.
However, among the top 10%, this average shoots up to
R2.79 million per person. This is concentrated even further in the top 1% at
R17.8 million per person, and the top 0.01% at
R486.2 million.
New research conducted by the South African Centre for Inequality Studies and the World Inequality Lab reveals how wealth is spread across the adult population in South Africa and how wealth distribution has shifted over the last three decades.
businesstech.co.za
But:
To enter into the top 10%, you would need a personal wealth of only R496,000. To be a one-percenter, your personal wealth would need to be just over R3.8 million.
So to hit top 10%, your entire wealth, all you've ever earned/held, has to be 28k EUR, so basically the median income in Austria.
Contrast this with South Africa's "middle class" vs Austria median (since Austria is mostly middle class I would say):
The same dataset also includes figures for what could be considered South Africa’s middle class – the ‘middle’ 40% of adults. For this category, the average middle-class adult has a personal wealth of R138,000 – and needs only R27,700 to meet the threshold.
Or about 8000 EUR if rounded up.
So will you consider South African "upper" class as rich or use the "rich" of other places?
Since any rule you do with the truly ultra rich will not work, if you check where the money is of the super rich like Gates, Rupert, etc., it's all tied up in companies and you'd possibly crash economies if you try and liquidate that.
The panama stuff is mostly different, those are usually illegal gains, things like bribes or whatever, there you need to empower the Hawks, bring back the Scorpions (who were already supposed to be re-established based on a court judgement a decade ago as an independent body, right now it's still Hawks mandate so political interference, etc., but Cele has said nothing years later, still crazy court is not finding him in contempt of court).