People raised with the same ideas as their parents/friends/society aren’t going to magically change just because they come from a younger generation. When Millennials start coming into power, there are still going to be Millennials on both sides of the political divide. The Republican ones will likely be just as insane, if not worse than the Boomers or the Gen Xers. It’s not like Millennials are just magically going to all be progressive and everything changes. Any of them getting into politics are going to become part of the mainstream political culture and internalize their political beliefs as they learn from their elders. The Right is much more organized about maintaining their ideas and pushing their beliefs, that’s why they work so hard to suppress the other side.