Techno optimists forget - even while presenting themselves as the ultimate materialists - an essential part of reality. I suspect one reason for that is that it's hard to say very much about it definitively, though we all know and recognize it very well. Its workings fill every part of our lives and society, at every level. But to them it's one of those things that's enough of a rounding error that it need not show up in any of their modeling of the world. And how would you account for it anyway? What numbers could say anything about it, about its limits?
The ad-men before them, who they inherit a perspective on the world from, and who their wealth as an industry is all tied up in now, and so who they put quite a bit of trust in - they caught a glimpse of it, surely. But they saw it primarily as a tool, and so ultimately missed the point of it entirely. Instead, they used what they saw to manipulate people's material action - to buy more coca cola, etc. They saw that as exactly the same as mastering this reality. But you could say slave masters achieved the same sort of mastery, if you believe that. Or maybe they didn't think it existed at all, and directing people's actions was what they wanted whether it was there or not.
But it is real, and still alive as long as we really are. It is the force behind our most purposeful actions, though like housework, it's invisible to the economic models. It's what I recon can "save" us, the way endless nuclear power will not, an artificial intelligence will not, a fully virtual reality will not, another financial system will not. It has already worked miracles and made the impossible and unthinkable real for us. It's what I put all my action and hope in now. I really don't need to have faith that it's effective - it is and always has been. But I have that faith anyway and in doing so, I add another voice to and amplify its force in the world.
Any vision for the future that doesn't have this at it's center, that trivializes it and replaces it with empty ideas and optimization - why would we want anything to do with it?
Everyone is able to understand stories about people (in books, film, etc), even ones far removed from us in space-time. We can recognize when a story is believable or not. That's our sensitivity to this reality at work.
By which I mean for example, the common economic assumption that agents in a market are independent and self-interested - as if family and friend relationships generally have negligable effects on people's behavior. As another example, it's telling that the only meaningful use you can find when searching for the words "friend", "family", or "love" in the techno optimist manifesto is "Love doesn't scale, so the economy can only run on money or force".
You could, for example, see the soul-aching and outsized cultural footprint of enslaved and slave-descended Americans as evidence against that. If you're a fan of the bible, perhaps the continuation and growth of the people once enslaved in Egypt could pursuade you otherwise.
For prominent American / western examples, see the labor reforms of the early 20th century, the recognition of the full humanity and agency of women, the civil rights movement. All of these are an ongoing struggle and not "finished", but do you think it was a technology that made them happen? Do you think they seemed at all possible before they finally produced results? This reality was their spark and is the engine for their continuation, period.