I agree that the Millenial generation (35ish to 18 yrs old) have, in general, given up on religion of their parents and in varied ways. Based on stats from my extended family (siblings, cousins, etc) and other families I know who started out as independent, non-sspx Trads (id say a millenial sample size of 300-350 people), here are the results:
about 10% don’t go to any church anymore,
approx 50% are now indult. They think the sspx is wrong and all independent chapels are also wrong.
25% are still trad but go to the neo-sspx, (which is currently quasi-indult) and they don’t really know their faith or understand what happened at V2 - because they didn’t read and study history, they just “went with the flow” and went to a TLM catholic school like their parents told them and nothing more.
That leaves about 15% who are still Trad, non-sspx.