What is "the dark simple curtain" in Ted Hughes' "Criminal Ballad"?

Question

In the poem "Criminal Ballad", Ted Hughes describes a chain of tragedies happening in parallel with a man's simple moments of life. One of these is the following:

And when he ran and got his toy squealing with delight
An old man pulled from under the crush of metal
Gazed towards the nearby polished shoes
And slowly forgot the deaths in Homer
The sparrowfall natural economy
Of the dark simple curtain

I'm trying to understand how the images in the last two lines are related to each other. So, the "sparrowfall" image is easy:

"'Sparrowfall' refers us to Matthew 10:29, where Christ is comforting the disciples by telling them that God's providence [...] covers everything, even the smallest details such as man himself would forget. For Hughes, this is no comfort to the old man at his death."
— Craig Robinson (1989). Ted Hughes As Shepherd Of Being, p. 61. Palgrave Macmillan.

Also, it might be helpful to note that Hamlet makes the same biblical reference, saying that "there is a special providence in the fall of a sparrow".

Then, when reading Matthew 10:29, we can also see that the "sparrowfall" is given in the context of commerce, and thus we can understand the meaning of "natural economy":

Are not two sparrows sold for a farthing? and one of them shall not fall on the ground without your Father.
— Matthew 10:29, King James Bible

But what does a "dark simple curtain" have to do with it?

Answer 1

‘Dark simple curtain’ is a metaphor for death: a curtain shuts out the light, and comes down at the end of a performance. ‘Simple’ means ‘uncomplicated’ but also has an archaic sense of ‘medicine’, which could allude to the idea of death as a cure for all ills.

The difficult bit is ‘natural economy’. The post suggests that it alludes to the price of sparrows, but I don’t think this can be right, since ‘natural economy’ is a type of economy in which there is no money or medium of exchange, and so goods must be bartered or shared. In a natural economy, you can’t sell two sparrows for a farthing, because there are no farthings; instead you must exchange them—but for what?

One way to make sense of this is to suppose that Hughes is gesturing towards the Christian doctrine of ‘economy of salvation’, the exchange of faith and works for eternal life.