^Except the Borg had a queen before TNG. Plus we saw hundreds of Borg cubes swarm a planet being assilimated, with the queen present.
Like I said, I'm sure there's some detail in a VOY episode somewhere that contradicts this. But I think we have to realize there are two fundamentally different approaches to this "problem." We can simply disregard everything we saw in the Borg's earliest TNG appearances and pretend that they were always as VOY depicted them (which was apparently what the writers of that show did) or we can try to come up with something that explains all of it, more or less.
That being said, I don't have a problem saying that the Queen personality may have come into existence before TNG, but because the Collective is so huge, it took a long time for her influence to work its way out from wherever it started.