If you look at what populations are expanding the fastest, and the ones that aren’t, it becomes clear a lot of things are going to turn out more Latin and non-European.
In the short term, until those populations become more modernized and successful, we can look for them to bury us numbers wise.
That’s not going to stop at the religious shores either.
They may leave us behind in numbers, but we need not let them bury us with numbers. Western nations need not admit them in the first place. Both the US and Europe could cut back legal immigration as much as we choose (even to zero), and we could stop most illegal immigration. With superior military strength, the West could protect itself from immigration-driven demographic destruction, even with dwindling numbers.
We (i.e. those who rule us) just choose not to do this. It is not inevitable.