[ars]

> These two groups also have high defection rates of around 50%

Not even close. Orthodox Jews is closer to 15%, and of those a majority stay within the Jewish community, but are less Orthodox. i.e. still religious just less so (eg. observe the major holidays, but not necessarily the day to day stuff, or maybe some of the day to day stuff that feels meaningful to them, but not everything).

> I can see secularism dying out long term, which I consider a philosophical tragedy.

Fallacy of the excluded middle. There's something in between Orthodox and completely secular.

You are also ignoring the dynamics - people are constantly shifting, there is never a stable equilibrium.