This assumes that no wealth has been created since 1990???
Another thing that stands out about the so-called 1% is that it consists of a large number of self-made people, indicating a high degree of social mobility. Effectively, your 1% are just financially very successful middle class.
How did they get there? The two billionaires I've personally dealt with, through hard work, stamina and sheer single-mindedness. Systemically, any of us had the same chances.