Indeed, we might argue that the reduced population back then was sustainable, because there was enough energy to go round.
But there is no shortage of energy now, since solar became significant, around 2005, there is lterally trillions of unmonetised energy (Economic product created), built up in the system now, and this is what is physically devaluing money now.
There is only one way to fix that, monetise it, and dish it out, because even if it is monetised and stuck in someone's account as capital, its worthless because it isn't being put to use.
So they have to dish it out.