It may be sped along by transplants, making more money than Kentucky is willing to pay its citizens, rich in comparison after moving to cheaper areas, but, almost insidiously, the vast majority will just come from children deciding to join the rest of the world, in the same way entire languages have died, let alone American subcultures: https://en.wikipedia.org/wiki/List_of_languages_by_time_of_e...
You mention your churches, and those are dying too, if you look at trend graphs: https://www.pewresearch.org/religion/religious-landscape-stu...
A really beautiful part of the process is how little you can actually change it. Regardless of whatever laws you push, regardless of any cultural loathing you have, Californication is inevitable. Your universities have thousands of international students, but if you get rid of them, children will still follow the trends of the rest of the world.
The most you can do is cross your fingers and hope that the inevitable doesn't lead to cultural "natives" being outpriced and left behind.
I'm not from California and I've never lived there; this isn't coming from a position of feeling scorned over not being welcome; I have spent less than a week in total of my life outside of the borders of states bordering Kentucky and Kentucky itself.
In person, it's unlikely you would see me as particularly distinct from your culture. I spent the day stitching wounds in myself and others from an accident that occurred while performing physical labor outdoors. Half of the people I talk to on a daily basis are tied intimately to their respective churches, one of them a pastor. I'm not particularly liberal. I frequently have dinner with neighbors, as conservative as they come.
It's just incredibly funny to see the death rattle of a culture; "stay the hell out" doesn't matter when your descendants a few steps down the line will be indistinguishable from Californians without a single Californian needing to enter your state at all. It's happening to the Indians, who had the same attitude and much more cultural distinction; it's happening to you.