Further to what previous posters have said , you also have to remember that the average JW really doesn't care less about anything "deep". As an experiment , go to a JW trolley / magazine stand and ask the pioneers to explain from the scriptures how they come to 607 BCE when all the authorities say it is 586/7. There are a few examples on Youtube of this. eg https://www.youtube.com/watch?v=XgTanYOAjRo
Invariably the pioneer looks anxious , suspicious , has a "deer in the headlights" look and then they tell the questioner to go to JW.Org ( "our website has all the answers"). Persist and they might make an effort , but most would struggle to give any coherent explanation or even find the relevant scriptures scattered all over the bible to support it - time , times and half a time in Revelation , the image of Daniel etc etc. Note what the pioneer says in the above Youtube clip "I'd have to go back and do some research on it." It's a core teaching , totally fundamental to JW theology. They shouldn't need to have to do that.
JWs ( including myself , for 40 years ) just broadly accept whatever the Society tells them without any real thought process , which is why they are so ready just to shrug off any changes , such as the various flip flops / abusurdities of the "generation" doctrine. When I tell my dog to go into the car or to fetch a stick, it doesn't hang around and ask questions. It just does it ( usually! ). Frankly - 586/7 / 607 doesn't matter , because what keeps JWs as JWs isn't really about doctrine. It's family , community , hope , fear , habit etc.