Lou, I must admit that I do think you'll have trouble with the very notion of an evolution of consciousness. It might be very difficult to get the implication of 'better' out of your mind as you read descriptions of systematic changes that rely on the previous foundation.
I have the same issues. But I haven't been able to ignore what seems like very good evidence. Fortunately, over time, I've come to see that there is no inherent claim at all of 'better.'
One small example: We can read rich descriptions of what the world and the self 'felt' like before a child was capable of, let's say, multiplication. Then we can read rich descriptions of how that shifts as the brain changes and opens up to such capacities. Those are very very diffierent and amazing, and can be seen in all cultures, even if mathematics aren't pushed. And, then, we can go on and see how these are all distinct from the kinds of states that come later if a person begins to do something like post-egoic work or enters into communities that encourage this.
Growing, to me, does not imply improving. It implies a kind of wholeness that is in a state of 'becoming' through time. Each period of development having treasures and challenges, each new stage losing important gifts from the earlier and needing to integrate them in new and creative ways.
The Spell of The Sensuous is a great example of what you'll never find in an 'original participation' context, but, just as true, our modern Idolatry will be resistant to such experiences because they are attempting to grow forward in a way that reintegrates qualitative knowing.