My belief, from what we know about this case, is that Lori was a survivor of some sort of abuse. She changed her name to hide from her abuser, and I think it was likely a parent or sibling, and others in her family allowed it to happen or refused to believe her which led her to want to sever her ties with the whole family. It's also possible she was a runaway or an orphan and the abuser was an older boyfriend or husband. Maybe she did have a loving and supportive family member (perhaps a grandparent) who she lived with for a time after she fled her abuser, but that person died around 1987 or early 1988, perhaps leaving her a little bit of money. Once the only supportive family member died, there was no good reason to keep her old identity and be vulnerable to her abuser finding her.
I think she had tried to get help from the police at some point but wasn't believed and felt like she was powerless to protect herself. I wouldn't be surprised if she came from a conservative, fundamentalist background where the man is the head of the house and is considered to "possess" the women in the household. Could be FLDS, but there are a lot of people who have beliefs almost as dangerous that are not as well known. There would have been very few people she could turn to; physical abuse is acceptable in such cultures and sexual abuse is blamed on the victim. That also, if she was sexually abused, would cause her to feel ashamed and blame herself. She would never feel comfortable disclosing that abuse to most people, and would not feel comfortable explaining why she left. And in such communities, young people fleeing and never being heard from again is not uncommon. I suspect her disappearance was not totally abrupt either; she left willingly after dropping hints for some time that she would be leaving and she was probably heard from a few times after she left but before she assumed her new identity. No one would've found it strange, probably happens quite often.
One thing posters here tend to do is suppose something dramatically bad & evil happened to her. LEK may never have been born into a cult or commune, never beaten, never kidnapped & forced into being a prostitute, or anything so dramatic. She might never have even been a stripper. The abuse she encountered may have been far more subtle.
I have in mind two examples from my own life. The first is the emotional abuse that a step-parent can inflict on a child, not intentionally or actively, but simply because that step-parent is indifferent to the well-being of the child. I've heard more than one step-mother referred to as a "step-monster". And if said step-parent has children of their own, many step-parents will favor their own blood over the step-child either intentionally or unintentionally -- something I can attest to. Said step-parent will even drive a wedge between the child & their surviving parent, further isolating & alienating the child. And if said child has found it difficult to make friends or otherwise engage others socially, it can result with the child growing into an adult who never forms strong attachments to other people.
(And yes, I am likely projecting my own misfortunes onto LEK's life. One of the pitfalls of theorizing about her is that because so little is known about her -- even after 1988 -- you can project your own self upon her, thus unintentionally telling the reader more about you than about LEK. It's one reason we need to know more about her.)
The example involves my Mom & her mother. For reasons no one is clear about, my maternal step-mother practically disowned her daughter & only child shortly after I was born; I'm the oldest child. (Yes, it was odd to grow up with a step-mother I never met, & whom was described to me as being "mentally ill.") I never dared to directly ask my grandmother why had done this after my Mom died, & now suspect she would have never told me the truth. The best guess anyone who knew the two why she disowned her is that the two women were close, & when I was born my Mom could no longer just drop everything to do stuff with her mother (for reasons obvious to anyone who has had children), & her mother interpreted this as some form of insult & reacted with anger. After my Mom died I got to know her mother's story better, & there is some reason to suspect my maternal grandmother had a fear of abandonment.
So she may have endured emotional abuse from a parent or step-parent, & left because of it. She changed her name to further remove herself from that toxic environment. If spring/summer1988's posts can be trusted, she did have someone in her family who gave her support & nurture, but who died within a few years of moving to Dallas. (Which is why I hope he was telling the truth.) After which she let all remaining ties to her past lapse.
I actually think her husband suspected something along those lines, which was the real reason he never pressed her about her background. He probably did believe most of her family was dead, but because of her complete refusal to discuss her childhood and discomfort with being asked, he inferred that something very traumatic had happened to her. Knowing that it was probably something taboo (like childhood sexual abuse and/or incest) he decided to simply not press her about her past at all rather than upset her.
As for the other stuff, like the lock box, most people would assume something like that is simply naughty photos or letters from an old boyfriend. If he knew she had the box when they got together (and presumably he didn't see her adding stuff to it at any point) he would know it wasn't an ongoing affair and thus maybe not something he needed to know about. Not everyone is as curious as the folks who hang out on Websleuths. Also, I mean, if he broke the lock she would know he'd been in there, and the resulting fight maybe wasn't worth satisfying his curiosity.
I guess I don't find his behavior as strange as most people on here do because I know a lot of people I consider to be "uncurious" in that they don't feel the need to look into things the way I do and they tend to either accept things at face value or come up with a very logical (and mundane) explanation for any mystery they encounter. I mean, for instance, there are a lot of people who aren't on Websleuths who if I asked about this story would find the Canadian immigrant theory the most plausible.
One of the many problems of this case is getting a proper sense of Blake. The ST story suggests that, at the least, he would score quite high on the Asperger's scale, & also may be detached from reality. Yet he is obviously intelligent: he earned degrees in engineering, & holds a mid-level position at Verizon. You don't hold, let alone get, one of those positions if you have no social skills. He probably understood -- & empathized with -- LEK far better than the ST story would suggest. But the reporter might not have suspected this because the Ruff family is likely accustomed to protecting him because he is "different" & so "helped" Blake with the interview.
But you bring up a good point about Blake's lack of curiosity. It may well be that he didn't pry because he wanted to respect her privacy, something that might have especially endeared LEK to him. It's not that hard to suppose. For example, I've never looked into my wife's purse -- although I could -- & have only a hazy idea what she keeps in it because I respect her privacy. Maybe he was hoping that by respecting her privacy that some day she would open up to him & explain what was the mystery in her life. Only things didn't work out for them.