The reason to reinvent the wheel when it comes to spirituality and enlightenment is that modern science was revolutionary. Although of course Nietzsche physically died, his point was that God wasn’t real enough in the first place to have died except in an ironic, cultural sense. Modernity ended only God’s relevance as a basis of our values. We can no longer take theism for granted or live out a theological life plan without wondering whether we’re acting like fools.
That applies more to monotheism than to Eastern mysticism or to certain kinds of esoteric spirituality, since the latter are more philosophical than religious or at least oriented more around practice than dogmatic theology. Still, science and the complementary philosophical naturalism throw into doubt many spiritual assumptions, such as that Atman equals Brahman or that souls can reincarnate or that escape from nature is metaphysically possible or that natural events have inherent teleological or moral value.
I don’t think it’s a mystery why scientists ignore old spiritual texts and traditions. You suggest it’s because scientists are prejudiced and beholden to a view of human progress according to which old and especially prescientific answers become obsolete or untested and risky. Sure, but scientists are also pragmatic, meaning they’re methodologically naturalistic. They see that scientific methods of inquiry work and they’ve made a business out of understanding phenomena by naturalizing them.
Scientists may see that certain spiritual practices likewise work, in which case they’d have to uncover the mechanisms involved and naturalize meditation, inner peace, and other perennial concepts. (There’s quite a conflict between scientific and Eastern medicine, and between the underlying ideologies.)
Even if scientists were barred from passing judgment on philosophical and religious issues such as whether God exists, mystical spirituality would hardly be in the clear. The problem is that the spiritual notion of enlightenment conflicts with the naturalistic worldview, and the latter is sustained by the overwhelming advances in scientific understanding and technological applications. Therefore, if you want to be spiritual in the late, hypermodern period, it looks like you’ve got to ensure your concepts and practices are consistent with the scientific worldview. That’s why we’ve got to reinvent the spiritual wheel. Otherwise, the spiritual practices are in danger of seeming like pseudoscientific frauds.
When I gestured towards aesthetics, I had more in mind than just advocating for an interest in art.
I’ve written a lot about this, but it would take us too far afield. I’ll just say that my suspicions along aesthetic lines are at least twofold. First, we may have to reconstruct moral discourse in aesthetic terms—again, to naturalize the former and render it comprehensible and respectable in light of scientific knowledge.
Second, I suspect the mystic’s vision of the world might likewise compare with universalized aesthetics, according to which everything can be perceived as though it were art. This needn’t entail a design argument for God, since the “artist” behind nature would be the mindless and absurd, but nevertheless supremely-creative natural forces and elements. In line with Nagarjuna’s Buddhism of “emptiness” and insubstantiality, we would need to detach from things and refrain from superimposing our essentialist presumptions, just as in an art gallery we focus on the artwork’s surface features.