Straight line extrapolations of present trends indefinitely into the future are rarely reliable. Plus the demographics are generally driven more by poverty and access to family planning resources moreso than the religious/demographic warfare angle nationalists tend to lean to.

In other words, if demographic balance was really the concern the most effective proven way to address it would be to invest heavily in education and healthcare in the community with above-average fertility. But instead the proposed policies always insist on more and harsher crackdowns on the minority group, which will be counterproductive at best.