I think it's pure propaganda. They know that there is no excitement anymore in JWdom. It's been over 100 years since 1914, almost 100 years since the "millions now living will never die" hype, over 40 years since the 1975 disappointment, over twenty years since the limit ran out on the old "generation" teaching in 1994, and two years since 2014 when they were hyping the "100 years of Kingdom rule".
There's nothing to excite JWs anymore. They're becoming complacent. The preaching work is fruitless now. They don't even really have a message anymore. I think the org knows it's losing, so it needed something to give JWs a boost of excitement that will last a few months or maybe a year. I think that's why they produced the bunker video - to buy them a little more time and keep JWs excited and under control.