I have read somewhere that the main reason capitalism has worked well over communism is, capitalism explicitly does not put a cap on wealth (and therefore, money) a person can accumulate since different people bring different values in society and the moment you put a cap on that, the person will lose motivation and stop even bringing the expected value for the cap that is being proposed.
I'm in no way arguing for/against taxing the wealthy and do not have a well-informed stance in this issue. Because, I also think money breeds money and if you are wealthy, the probability of you gaining more wealth increases exponentially.
Personally, I think maximum salaries or maximum wages will not work since it inherently has some disadvantages - do you propose an absolute maximum value for everyone in this world? or do you propose region wise or based on some other criteria? If region wise, just like remote work salaries, people will start gaming the system etc etc ... I think this discussion goes far more than keeping billionaires rich and discounting the segment of people who might end up in that list sometime in future, but maybe they are holding themselves back from giving more value to society because of these laws?