Have you ever heard of the lump-sum tax system?
It's a special kind of taxation, based on a fixed amount, rather than on the real circumstances.
What is interesting is that it is "reserved" for the ultra-rich people who don't want to go offshore to some distant countries in order to pay zero or really low tax, but rather wish to have more predictability regarding their tax payments.
The country that is the most famous for allowing this type of tax is Switzerland, which gives super-rich people a privilege to negotiate and fix the amount of their tax.