I think building and theorizing a new monoculture is exactly the wrong place to start. Not that you are, you say at the end it is beyond one builds a truly healthy world/society.
I think leaning away from emotion and into metrics is the start.
I think Paulo Freire has the right framework to start viewing how this should go, though he would probably say "These are my ideas, make your own." And that's the key, in my opinion -- live by your own imagination, not on the rails that the world lays down (which usually are laid down by elite power players, not the public).
I'd say it's this unfettered freedom to do literally anything, seems to be a huge issue to me. It's displaced our own ability to imagine, and has us just doing things in the literal world, because that's what the rule book says.
One dude's freedom to make a rocket engine car meant someone else machine parts for a paltry wage and will never have the money to assemble a rocket engine in their garage let alone the entire car. That's how it has to be -- or so the story has gone.
But the rocket car guy and voices in the thread seem like that's exactly what we should be aiming for. OK, but do it without needing a huge factory manned by low-wage earners. Suddenly, Americans are less free, and chafe quite a lot at that notion. The world should be theirs, and if that means other workers in other nations have more of a say, well that can't be right. Or so the conversations I've been a party to for years have gone ("America went through a growing up phase. Those countries should too." as if there's anything more than social opinion requiring that it be this way.)
First world freedom for Rocket Car Guy, who mocks the notion that's absurd and should be regulated, meant a wage slave somewhere was the one doting on the actual mining, smelting, etc.
The same lack of introspection is all over this site. "Make more apps, build more datacenters. Cause I have to sign up more users." Get people to be "more digital". Despite that not being a physical law of reality.
It's contemporary vanity: obviously the world is becoming more digital, so we should lean in. Ignoring the reality of what that requires, and that it's rather a bit fascist to assume future folks would want to go that way. So here comes another global monoculture to fail in a generation.