jgnat, you've been very kind to put up with what might otherwise seem like me "digging" at you...and you know me well enough to know I'm not! That's not my agenda, either with you or any other poster on JWD.
As for as your observation:
The succeeding generations have not managed to maintain the vitality of the old.
I agree. But I would attribute this more to a demographic, than an essential, aspect of human nature. Thus my statement that the WTS of the 50s has never been recaptured (words to that effect). But why? Was it because there was a fundamental shift in the human psyche? No; imho, it was, and continues to be, simply a result of the post-WW2 babyboom, the effects of which are observable across the entire spectrum of world society, and which are looming upon us to this day in other non-religious ways (immigration, emmigration, currency exchanges, etc.).
Interesting that you mention the Quakers. They have, indeed, "suffered" from their tenets...and yet there is an interplay between the Quakers and Mennonites that ensures the perpetuation of both.
As someone famous once said: "You can take the man out of the religion, but you can't take the religion out of the man."