Hi my friend y not! It is good to see your post again!
You wrote: The human bhavas one lives through outside of a Buddha sasana, without ‘the Dhamma in circulation’, or without any possibility of access to it, even during a Buddha sasana, does away with the value of a human bhava. That will be the case with most, even now. One is left to one’s own devices, as high as those may be, contemplating for instance, the implications of eternity, infinity, even perhaps to getting the fleeting idea from the material world all around as analogy,that all phenomena, even mental ones ,must have causes as well as results. But there is no way one could discover by oneself all that a Buddha reveals out of his once-in-a (or so many)- kappas Purity of Mind: the 31 realms, the 4 Noble truths, Tilakkhana,PS ,the intricate details in Abhidhamma and so on.
The human bhava/realm is a pivotal realm, in which beings have the most power to change their destinies, especially during a Buddha Sasana. However, even outside of a Buddha Sasana, it is true too, though to a lesser extent.
I state the above, having read that beings in the apayas have very little power to effect changes in their destinies, and think that deva and brahma beings also have little opportunities to do meritorious deeds or to develop compassion, as they encounter very little suffering in their realms.
Outside of a Buddha Sasana, in the human realm, there could be righteous people who could be from other religions, or who live moral lives, as a result of having developed good gati. They have the opportunity to develop their paramitas, waiting for a future Buddha to come along.
Then there are other moral individuals who can continue to develop the fertile ground to fulfill their aspirations made during any prior Buddha Sasanas. They, too, await a future Buddha.
Hence it is important to cultivate good knowledge of Buddhadhamma, develop good gati as well as to make aspirations during a Buddha Sasana to attain Nibbana , with or without corresponding conditions attached. For example, when Sariputta and Maha Moggallana many aeons ago, at the time of the Buddha Anomadassi, were born as the brahman youth Sarada and landowner Sirivaddhaka, they made the aspiration for Chief Discipleship, and eventually became the Chief Disciples of Shakyamuni Buddha.
Then there are the Paccekabuddhas, who realize Nibbana solely through their own efforts, but are unable teach the Dhamma. They realize their ultimate goal outside of a Buddha Sasana.
So, even outside of a Buddha Sasana, the human bhava has its own value too, though it is of course still anatta.