I feel like I haven't heard the phrase "how come?" when "why/why not" would work just fine, for quite some time. Enter these newish episodes of Law and Order, and I've heard it used at least 5 different times. Is this a phrase that has some kind of legal backstory, maybe it goes to a person's motivation for doing something in a different way than "why/why not"?
It feels like lazy writing but I'd love to know otherwise!
#HowCome
No.32 on The Top 50 Official U.K. Singles Chart on my 2nd Birthday - The Archive of My Life

With Ronnie's role with the Faces now just a memory, the co-founder of both that group and its predecessor the Small Faces, was now striding out into new territory... #ClassicRock #RockMusic #70sMusic #MusicHistory #UKCharts #1970s #RetroMusic #BritishRock #RockHistory #Vinyl #SmallFaces #RonnieLane #SlimChance #HowCome #FacesBand #ModRock #FolkRock

The Archive of My Life

#HowCome?

On my last toot
#UScantDoMaths

YT Channel 'Strong Towns'

has a short one:

"We used to build starter homes, but now they're mostly illegal"

https://www.youtube.com/shorts/Kh4zSYPCAO0

We used to build starter homes, but now they're mostly illegal

YouTube