Origiinally, I think, Pastor Russell believed that there were consecrated Christians spread throughout the various churches of Christendom, and that his role was to gather them together into the true church.
As time went on it became more and more necessary for a person to be a Watchtowerite to attain salvation.
It's all a bunch of crap, a few steps below vinyl siding salesmen. What they want is your money, an they'll promise eternity to get it.
(No offense intended to any vinyl siding salesmen in the audience.)