If the strength of population growth, hard work attitude and morals ever come back from the 50s we'll be ok. Since the internet seems to want the opposite, I guess we're just going to burn.
Do you want Idiocracy[0]? Because that's how you get Idiocracy
Quite the opposite it seems looking at history.
I would say conservative Catholics rather than just traditionalists.
Both SSPX and Opus Dei have larger families, and both have a strong conservative streak. But SSPX is traditionalist, whereas Opus Dei is more "modern conservative". Opus Dei is officially enthusiastic about Vatican II (provided it is "interpreted correctly"), SSPX refuses to accept it. While both celebrate Mass in Latin, SSPX insists on using the old (pre-1970) Tridentine Mass in Latin, whereas Opus Dei's Latin Masses are the contemporary Mass in Latin. Opus Dei emphasises obedience to the Pope (although Francis makes that painful in a way that his predecessors never did), SSPX insists on a duty to disobey papal decisions it believes to be erroneous
Like a third of Mormons leave the church. Ditto for Catholics. Probably similar for the rest, but I haven't looked up all the statistics.
I'd go so far as to wager that in America today most non-believers come from religious households, with second-generation-non-believers in the minority.
Ultra-Orthodox Jews (Hasidic/Haredi) and Old Order Amish have very high retention rates, by some measures >90%.
Mainstream Catholicism has very poor retention rates – there is a quip that ex-Catholic is one of America's largest religions. However, if we look at highly conservative/traditionalist groups like Opus Dei or SSPX, the retention is much better (although I don't have exact figures).
Mormons are definitely showing signs of transitioning from growth to decline, at least in the US. However, given other religious groups I mentioned appear to be avoiding that, it may be more a story of mistakes of the Mormon leadership than anything else.