No, they preached a very unpopular, often ridiculed doctrine. The logical conclusion is that they believed what they preached. I am not claiming that Watch Tower doctrine, especially their approach to prophecy, is logical, scriptural or in anyway good. But one doesn't promote a doctrine that brings you ridicule and opposition if the sole goal is to sell books.
Many people believe irrational, unfounded things. Doing so does not mean one has a selfish motive. Just that they're irrational. The Watch Tower movement in Russell's day is part of a larger Millennialist [non-Adventist belief in Christ's near return] movement. Its doctrines overlap with other parts of it. Nothing in it is unique beyond an aggressive evangelism and Russell's personality. The total mix of doctrine is what made Russellism unique.
There is a disconnect between Russell's era and today's Witnesses. Witnesses are lineal descendants of the Russell era Watch Tower, but it is a different religion, one that Russell would have rejected. Still, I do not see Witness authorities as seeking selfish gain. There is no more evidence for that than there is for Russell. No matter what one thinks of current Witness belief, they plow all their money back into promoting their doctrine. So they're 'true believers,' even if one finds their doctrine unscriptural or irrational or both.
An evil motive is not necessary to mislead or abuse. Sometimes a firm conviction that we're right, left unchallenged, is enough to cause abuses.