[xrange]

>What makes the perspective of someone in a position without power more authentic than the perspective of someone with it...

Well someone not in a position of authority or power doesn't have to worry about losing said authority. If you tell too many uncomfortable truths or offend the wrong people, you may in certain instances loose some of your power. So it makes sense that the likely hood of getting an "authentic" story seems to get less and less as the person telling it rises in stature, power, authority.

[nostrademons]

Someone who's in a position of authority or power doesn't have to worry about gaining said authority, while someone who's not very often does. Rationally, the two situations are equivalent. (Psychologically they aren't; there's a cognitive bias that causes people to weight losses higher than gains, but there's also a cognitive bias in others that makes it easier to avoid losses than enact gains, so they roughly cancel out.) You can't draw significant conclusions either way along this dimension: the willingness to sacrifice authenticity for power is a mark of the security<=>insecurity axis, not power<=>powerlessness.

[xrange]

I don't know that those two axes are orthogonal. It seems like there is an asymmetry between gaining power and losing power. I think we can agree empirically (if not definitionaly) that there are fewer people with power / status. There are a lot of things besides not offending those others that keeps people in a position without power. If you know that these other factors are keeping you low status, then you have less incentive to pretend to be something you are not. But a single offensive comment can sometimes dislodge someone with power.