I think the point of these assumptions is that they hold true in a majority of cases, and are necessary for the system to function the way it does. If nobody bought into this stuff, then wouldn't the system fall apart?

Anyway, no matter how much a client fights for equal power, if you are disclosing difficult or painful stuff and the other person is not, and they are acting as authority or parental figure, and you have a history of abuse or abandonment and are generally vulnerable, and the T is setting most of the rules and controls the apparatus of therapy… then there is a power deficit the moment you walk thru the door.

I have been hurt by therapy, and have done a lot of reading, and I would now challenge much of this, as you describe. And so I agree with the idea that the client should narrow this power gap as much as possible, to protect themselves and to make it more collaboration than hierarchy.