In my opinion, "happy" is a "compared to what" thing.
We're programmed to make the best of whatever situation we're in in order to survive in it. So most of us do that.
And when you're doing that, you can look quite "happy" to the world (and even to yourself, to varying degrees, depending on your personality, I think) when you're really just making the best of a very bad situation. And when you've never experienced any of the things that you might later find truly make you happy.
And when you accept as normal quite horrible, imprisoning things -- because you've never seen or experienced anything better so you don't know that anything else exists. Or you've been taught that any other way of living is a bad, dangerous thing that you have to shun or get into horrible danger or go to hell or whatever.
My family member who figured out in her 80s that she'd been treated worse than shit by a couple of people she'd given her allegiance and love to until they died was described with the following tagline in her senior high-school yearbook: " So lucky! If only all our spirits could be so happy and serene." (Yes -- this is the kind of thing a high-school yearbook staff wrote in the 1930s!)
She smiled and didn't complain. Complaining and not smiling weren't permitted. But everybody saw the smiles and heard no complaining, so their minds went right to "Happy!" "Serene!" "Lucky!"
I helped push her toward understanding what had really happened because of the way I complained about my own quite similar experience -- and a large part of me thinks that I did a lousy thing by doing that. (However, she didn't really believe me when I bitched about such things -- she tried her best to just write me off as a grump!)
What finally pushed her over the edge was that, as an elderly woman, for the first time she made some friends who talked a lot together about their lives. And they all expressed horror at things she described that she had always told herself were perfectly normal and fine. It was like a bright light had suddenly come on. LIke Helen Keller with her hand under the pump -- "Wa....wa....water!" And in this case, I can't decide if it was a good thing or a bad thing.
But I agree that it's perfectly possible to go through life imprisoned and never know it. And that way you can figure you're happy, even if your happiness isn't something a lot of other people would recognize.
In a way, that's my wish for the Duggarlings .... because who wants regrets?
At the same time, though, I hope they raise their kids differently.....
And they probably will, to some extent, anyway. They were sucked into this lifestyle. They didn't choose it. So that almost certainly means that few of them will have enough energy to promote and enforce it the way their parents -- first-generation zealots -- did.