Someone has testified somewhere

Now God did not subject the coming world, about which we are speaking, to angels. But someone has testified somewhere, “What are human beings that you are mindful of them, or mortals, that you care for them? You have made them for a little while lower than the angels; you have crowned them with glory and honor, subjecting all things under their feet.” Now in subjecting all things to them, God left nothing outside their control. As it is, we do not yet see everything in subjection to them, but we do see Jesus, who for a little while was made lower than the angels, now crowned with glory and honor because of the suffering of death, so that by the grace of God he might taste death for everyone. It was fitting that God, for whom and through whom all things exist, in bringing many children to glory, should make the pioneer of their salvation perfect through sufferings.

- Hebrews 2.5-10 (or if we're go to with the spirit of the passage: "Somewhere")

Here's the question: if we don't currently see Psalm 8, is that because our eyes aren't good enough, or because it's not (yet) true? Have the many children already been brought to glory? If there's a 'pioneer' and then 'many children', doesn't this imply a gap between what happened to Jesus and what is yet to happen to us? And if that all seems obvious, then why is Jesus already 'perfect' if he hasn't finished his job?
Twelve points for naming the city that contains this beautiful early medieval mosaic.