I am guessing that you have some background of philosophy behind this which I am not precisely aware of,
I do indeed.
isn't power a far more fundamental component of what men really place as their 'top value'?
No I don't think it is at all, and with very good reason.
But I'm not focused on what man's top value is, only on the fact that it can be determined by reference to man's nature.
I respect what you say, that there is no such thing as man's nature. No such thing as Pythagoras theorem either.
He does not need to be consistent with all men's desire precisely because he is not all men, but a unique individual who is only subject to and capable of self-satisfaction.
He is unique, yes, but a unique manifestation of a specific type of entity. The essential attributes of this specific entity are common among all sub-species of that entity.
eg essays, novels, notes, origami, and wasps nests are all organisations of paper. These specific "unique individuals" have their own specific character but also are made of paper and are subject to the nature of paper. They're all combustable.
So, if you consider any unique man it is possible to stipulate facts about his nature before you even know specifics about his personality. Perhaps that he is bipedal, and combustable.
It would help, for example, to know why something of such obvious utility would be so totally overlooked by people who are trying to prove precisely what you intend to prove? It does not seem, empirically, that it really is self-evident either to supporters or detractors.
Inexplicable evasion, indeed.
This form of reasoning, as practised by millions of students of the triangle, is quite able to be applied even by uneducated persons. Of course, if you're wretched at trigonometry you might like to obscure your workings from view while praising to high heaven its conclusions in order to (1.) blend in with the status quo, and (2.) enjoy the wonderful fruits of truth even if it is not understood.