Fear of hell is in our dna...

[Angrboda]

I'm sure threats of hell are a potent factor in religious conversion. It's also arguably a greater factor among children and the young, among whom most religious conversion (or indoctrination) occurs. But it's not as clear that threats of hell are as effective in maintaining belief once it is established. Perseverance of belief as well as parental influence are likely factors there. Once you believe, for whatever reason, it's harder to stop believing than continuing along the same path. Thus threats of hell, parental influence, and perseverance of belief likely make up a perfect storm guaranteed to turn out faithful who, though they develop more sophisticated views ad hoc and post-conversion, likely owe their faith to early vulnerability having nothing to do with any "nobler" motives for believing.