Who is going to pay for this dream....or nightmare?
The same people who fund armies and wars.
And those who will profit from it in the future, more.
I know it's not gonna happen. But the OP is asking what we think
should happen.
I think that is what should happen.
The world could easily afford it given a a change in few priorities.
Just to give you an idea: the world has spend a budget of 9 trillion in fiscal support in response to covid. And that's thus not even counting the purchases of masks, vaccines, additional budgets for research and staffing of the health sector, etc.
And all that in just 2-3 years.
When confronted with a crisis, the world is very capable of shifting gears and injecting massive funds.
Also, why exactly would you call it a nightmare?