havesomeseichel,
What are you talking about? The vast majority of Jewish people are non-carriers. And the majority of shidduchim are between two non-carriers. Therefore their children are also non-carriers. So it doesn’t pass on the next generation. At no point with current practices will a majority of people be carriers. (Even if children of a one carrier parent becomes a carrier. And I’m not even certain if children of parents where only one is a carrier automatically become carriers themselves.)