No they don't believe it, it's a marketing ploy. Follow the money. They produce a product, publications, that are profitable because of free labor and with those profits and donations they invest in all kinds of real estate (and on Wall Street). Mortgages for Kingdom Halls provide a stable return. Assembly buildings are very very profitable. Rental property, office buildings etc. They keep them untill they generate a real return then sell them. The WT makes money hand over fist.
On the other hand they don't invest more then a token amount in getting the message out there. The world is ending ? Billions will die? Let's buy this valuable real estate in Brooklyn and hold on to it for a decade or so.
They embrace the new technology that allows them to print more stuff more efficiently and build better permanent buildings but when it comes to getting out the word they do not embrace modern technology but a method that is 2,000 years old and free. Plodding house to house.