I haven't been around it for a long time, but I do know a case that fits your theory. It is the story of the weirdest fader I ever knew. This was a guy and his family who came to Okla. City from California. He moved because he was in the aerospace industry and wanted to be transferred to a plant that did not do defense contracts. He was a model witness for most all the time that I was active, volunteer, servant, aux pioneer...
He faded out a little before me. As far as anyone could tell, it had nothing to do with doctrinal issues - although I think 1975 had some small effect. What little he would say, I think it was an offense over hypocrital acts of some locals. He was a very close friend both before and after I was DFd at the Ray Franz group time. As he had already faded, he still talked to me and was supportive of my situation. About 15 or more years later (1995) he retired and sold his business.
Now, it gets weird after a year or two. He starts going to WT meetings but will not comment. Then, he starts going back to book study, then other meetings and service. We were still in touch, and I had to ask why. He said "well, I'm retired now and I missed seeing my friends". I said, "yeah, OK - but how can you get past the fact that they LIED TO YOU?" So he said "OK, so they lied but I still miss them".
Pretty soon he is more active than he was 25 years before - like he was making up for the faded years. Recently he decided to shun me like he was told but sent me watchtowers for quite a while. My take - he is paying the activity and loyalty price to have his old friends admire him in his later years. So, maybe some of the ones you mention are doing this for more personal reasons than religious ones.