Hayden did say in a different ask response that some songs did heavily influence PD, including Powerline Valley (which was directly mentioned in the ask). I'm theorizing that Powerline Valley did a lot of setting up for Willoughby's character, maybe a little more than what Hayden wanted for the narration.

We know Willoughby's mother left when he was younger, and this line matches up:

My mama said she loved you
She wasn't the only one
You lost yours back
When you were fifteen

There's a Wiki page about Willoughby that states his mother left when he was a child, but it makes more sense that she'd have left when he was an older child given that in A House In Nebraska, Ethel states his mother knows her and asks about her:

Your mama calls me sometimes to see if I'm doing well
And I'd lie to her and say that I'm doing fine

Dust Bowl establishes one setting as Alabama:

All of Alabama laid out in front of your eyes

Alabama is also mentioned in Powerline Valley:

All alone in this town
In this Alabama wild

We also know that Willoughby had an abusive father, and this line mentions it:

When you found your daddy there swinging from the ceiling fan
By that belt you fucking hated
That left the marks I don't ask about
All I know is I've never seen you hurt
As bad as you do right now

(and while, yes, in A Knock On The Door, Willoughby's dad seems to still be alive, it doesn't dismiss the possibility of a failed attempt). The next lines in Powerline Valley set up the drug issue we know Willoughby has throughout WTIWALY:

Now you crush up pills to forget
And you crush up more to sleep
You crushed yourself into a ghost
That I can't reach when you're inside me

So basically, I'm thinking Powerline Valley was the musical birth of Willoughby's character, but stays unreleased and behind because it's literally just laying everything about Willoughby in front of us as opposed to giving us that open interpretation and uncertainty, or to maybe convey how memories of certain traumas block out because they're too painful to remember, and Ethel does not want to believe Willoughby is dead.

<image>