You speak of "power" as an abstract. People are unique, with different talents, abilities, knowledge, and value scales. Sometimes this means a real power difference. The question is in how this power is used.
As I have stated elsewhere, "capitalism" is used in English to describe two distinct and oppositional concepts: voluntary trade, and political interventionism. The former does not lead to the latter. I see a lot of left anarchists conflate the two concepts and disregard the essential distinction.
I use the term "market anarchist" in hopes of avoiding this pointless semantics debate, but you brought it here.