(2/n)
...depending on the country (and the times), and lacking any loss-carried forward (or backward), the average tax rate will mostly be between 15-30% for the amount below that million (varies widely and has other factors, depending on the jurisdiction.)
Likewise, if you make 1 bn, you will not only get to keep 100 m (10%), but way more (850 mn to 700 mn. in my rough estimate.)
****
On a more political/societal note:
In a world where 26 billionaires (according to the AUW...