I've never understood the appeal of the argument that Bronze Age humans needed to be fed myths and untruths because they couldn't have coped with full scientific reality. As both of the above quotes show, it leans heavily on metaphorically identifying Bronze Age humans as children, modern humans as adults and the history in between as a kind of intellectual growing up - a fundamentally flawed analogy, as Bronze Age adults were not mental children but had brains indistinguishable from ours. Bronze Age brains could have coped as well as ours do with scientific reality, and it should not have been beyond the capability of an omnipotent deity to let them see that reality from the start rather than feeding them untruths that would impede intellectual and technological development for several thousand years.
Your argument rests on several false assumptions:
1) That these metaphors were needed because of the primitive nature of bronze-age humans. In fact, God has always spoken using huge amounts of metaphor, analogy and parable. When dealing with concepts as abstract and cosmic as these, this is really the only way to communicate. You might as well argue that modern poets should write poetry instead of prose, because we're mature enough as a species to just come out and say things.
2) That brain size is a good measure within a species for cognitive maturity. Between species, brain size is a great measure of cognitive ability. Within a species, not so much. WRT humans, not only do many people with very low I.Q.'s have larger than average brains (including a large part of the autistic spectrum), but people with identical brain sizes can have wildly different I.Q.'s.
In particular, cross-cultural studies of Piaget's stages of cognitive development show that without formal education, most adults will not reach the fourth stage. The window of development closes, and this is why many people who grow to adulthood without formal education demonstrate concrete operational thinking but not formal operational thinking.
Formal operational thinking includes the ability to think abstractly about abstract ideas, which is what is required for sciences AND religious understanding. Bronze-age people, lacking this kind of education, would therefore be likely to struggle with such ideas. They would need metaphor and parable even more than the rest of us do (see item #1)
3) That God's purpose would be better served by being more scientifically accurate. God has actually commanded us to seek out knowledge. This purpose is hardly well served by just telling us everything. If He did that, then we would count those things as true not because we tested them repeatedly, but because He said them. We would gain the information, but would not appreciate it or build on it properly.
God's purpose in telling a parable is to teach a lesson. That lesson is not improved by additional scientific accuracy. On the contrary, the lesson could easily be bogged down in unnecessary details until people missed the point.