I think Watchtower has done some things, not necessarily for this reason, to ensure there isn't another schism as when Charles Taze Russell died. With Watchtower taking direct control over the property rights of every Kingdom Hall and congregation funds it seem really unlikely for that to occur.
In the past, there have been whole congregations that parted ways with the Watchtower. I remember as a kid always thumbing through the telephone book inside our hotel rooms. I would look up the local Kingdom Hall in it. One time I came across two separate entries. I asked my dad what the second one meant (It had a different label than "Kingdom Hall of Jehovah's Witnesses). He said it was most likely a whole congregation that "left the Truth." You could do that if your congregation owns the Kingdom Hall like back in the day.
Watchtower says whatever it wants and the Witnesses believe it like their lives depend on it. They can tell you the sky is yellow and I can already hear Witnesses saying "Yeah. Yeah. I can actually see it now. The sky is sort of a yellow."