Quoting from the article - "All argue that a weakened, feminized, coddled, birth-controlled Western culture has become too soft and impassive to resist invasion and dominance by supposedly more muscular, more fertile and more aggressive Asian and Islamic cultures."

I think this sentence best describes what is happening.  Both of my grandfathers came from late families - 12 children combined.  I had one sister - my wife no siblings.  While we had two children both are in their mid 30s and we are not (yet?) grandparents ourselves.  

Use the upcoming Canadian census figures coming out later this year to see the movement of 'the baby boomer bulge' and compare the ethnicity breakdown for the 2016 census compared to, say, 1986 - then project the change 50 years into the future when almost all of the abby boomer generation will have died off.
US census data will reflect a similar pattern.  Given the population data the Trump phenomenon should be no surprise - and thus taken very seriously.