Europe does all of that including taxing the billionaires. It just works. All you need is the proper law and to vote for the proper governments to enforce them. It just works after that.

And it can happen in the US too - billionaires ran entire country at the end of 19th century. People voted for anti-trust laws. Billionaires stopped being feudal lords exempt of scrutiny after that. Then people voted for left-wing policies in 30s and 40s. After that, the rich was taxed up to 90%. And that period is known as the 'American Dream'.

So, it happened before. It can happen again.