In that power is mostly perception, and therapists work to actively guide the perception in the room, does it not stand to reason that therapists hold the greater bounty of power?

While it's valid to gauge power based simply on the dynamics of client and therapist each having the right to disengage with one another, it does seems oversimplifying, ignoring all that happens in session where it is the client who exposed and vulnerable, who reveals, who looks for guidance -- none of which happens with most therapists. Certainly most of mine would have sooner told me an anecdote about another patient than about themselves, which being third hand wisdom always sounded like it felt impersonal and disingenuous even to them.

Sure, ultimately we give them that power (albeit with plenty of encouragement from them), but what other option? That's the process. To lay ourselves bare, for them to comment and judge our every micro-idiosyncracy. Imagine having a real-life relationship like that, where you were totally honest with someone who perhaps took notes during your conversation, who never shared about themselves, and to whom you kept going back for more of the same kind of interaction.. it's only natural that the power balance in a relationship like this would become skewed.

Which may be okay for some people. Personally I prefer to engage with those who are confident enough in their abilities not to require that type of imbalance, and who have enough of an understanding of the benefits of collective intelligence to be willing to convene with more equal footing. My personal experience has been that many therapists are not highly functioning where this sort of confidence and understanding are concerned though, perhaps having too soon come to heavily rely on power imbalance. (This is not dissimilar from the common complication of a parent-child relationship in which as a child becomes an adult, many parents are unwilling to ever fully relinquish the psychological power they once wielded effortlessly, in order for the relationship to evolve. The parent becomes accustomed to the power that the role allows, enjoys scolding and directing and criticizing and may even let these aspects spill over into other relationships.)