> you wouldn't necessarily expect ancestral "defaults" to be optimal
I like the term ancestral defaults and indeed, we've come a long way since then and our biological and environmental reality is substantially different.
There is this book series Mortal Coil by Emily Suvada which imagines a future where technology has advanced enough to allow one to tweak their genome as easily as we use apps on our phone today. It was a fascinating read.
>our biological and environmental reality is substantially different.
As true as it might be, that does not mean that it is possible to work around evolution to change ourselves to fit better with the new reality.