I was a devout JDub. Raised in the lie. pioneered, MS and Elder with many responsibilities.
Yes, I had heard some things that didn't add up but I buried them as I waited on Jar-Hoover to vacuum them away.
It was during my service as an Elder that I saw the cracks, the lies, the deceit the weirdo reasoning. I was badly treated by members on the body who wanted nothing more than glory and power. I resigned and decided to build myself up 'spiritually' so did some REALLY DEEP study into 607BCE and other stuff. All the stuff I had doubts about but had burried.
Guess what! Yup! My doubts weren't answered but multiplied due to washTowel nutty reasonings.
The 'overlapping contempories' was one of the final straws - what a crock!!!
I didn't want to read 'apostate' stuff as I wanted to give the washTowel a fair hearing.
I started to read 'Combatting Cult Mind Control' by Steven Hassan. To this day I haven't got beyond chapter 4.........I don't need to! It all added up to WTBTS+DOCTRINE=DESSTRUCTIVE CULT!
Bottom line. I walked out of the KH one day and told my family that's it I quit!
SO. In answer to the thread question I'd say
Is It Impossible To Reach A Devout JW ??? No. But it might take something to happen to them that puts the WTBTS in negative light first.