That is assuming that the person that owns the wealth is the sole driver for growth of that wealth. Can we stop pretending that being wealthy is empirical evidence that you know how to grow an investment?
It doesn't matter what the driver is, if A over time has continuously demonstrated the ability to achieve higher returns on their wealth than B has, absent other evidence (ceteris parabis) it's reasonable to assume this trend will continue in future. Yes there are some people who got wealthy only through inheritance, but the money they inherited still had to be originally created by someone capable of generating wealth.
"it's reasonable to assume this trend will continue in future." -- except its not, that's why we had the 2008 crisis -- I can generate 20% returns 9/10 years, but on the 10th year I tank the whole world economy with my risky subprime bets.
This completely ignores the fact that below a certain line, B no longer gets to participate as freely as A in the space. A gets to demonstrate higher returns as well as higher losses and still be considered a better option even though in absolute terms they have contributed greater losses than B. "Reasonable to assume, follow the trend" is just so braindead, and basically no better than flipping a coin; if you're are absent of any other evidence, then maybe you shouldn't be using that to segregate the population in to the poors and those-who-know-better.