And 63% of all people in the country are white. In 2000 that was 69%, in 1980 it was 80%.
In other words white people should still make up the clear majority of every single demographic, lacking any biases. In terms of wealth they should be disproportionately ahead because of the fact that migrants are very rarely rich. So e.g. imagine you had 80% white and then you add enough migrants to bring that down to 70%. The number of rich individuals, as a whole, will probably not change much, meaning it'd be about the same as when whites made up 80% of the population, yet now whites would only make up 70% of the population. So this creates a relative over representation among the wealthy without any sort of bias other than in the socioeconomic composition of migrants.
Where things get really bad though is fertility. In modern times wealth and fertility are sharply inversely correlated. This [1] is a graph of fertility in families ranging from those earning $200k+ per year to those earning < $10k per year. There's a disconcertingly, practically linear, drop in fertility as people earn more money. Those earning less than $10k a year show a 50% higher fertility than those earning $200k+ per year. As a result of this, poverty also multiplies much more quickly than wealth. Due to the nature of fertility (2.x = baseline for sustainability, not 0), this also results in a much larger than 50% effect on relative population sizes. E.g. a group that has 1.5 children on average will gradually approach a population of 0, while a group that has 2.5 children on average will gradually approach a population of infinity.
This creates quite a difficult problem to solve. You can't solve poverty when people becoming wealthy means they stop reproducing in sufficient numbers while, at the same time, those who are at the very bottom of society are pumping out far more children than they could ever independently afford to support. It's like you take one step forward and two steps backwards. And while this is happening you also then start to see increasing social instability and divisions. No idea where all of this will play out but there's no doubt we live in one of the most interesting times in our species long existence.
[1] - https://www.statista.com/statistics/241530/birth-rate-by-fam...