This is a not good line of thinking. Good genes? What does that mean, greed? Competitiveness? What about positive human traits like empathy, compassion, generosity and contentment? The things that make society work in the first place? Plus it's not like billionaires have more kids. "Leeches" aren't poisoning the gene pool... Your "leeches" are the gene pool.
I agree we should strive for a system which incentivises empathy, compassion, generosity and contentment.
Billionares do not have more kids but wealthy people have the capacity to have more healthy offspring, irregardless if they actually do.
I have said nothing about poisoning the gene pool, i am not a eugenicist and far from it. But every system has free-riders (leeches) as game theory predicts, we should try to counteract this behaviour not reward it.
