Originally Posted by EPOCH6

To understand the link between roots genres and their subgenres you always have to look at the first wave of artists, not necessarily what the subgenre looks like today almost 40 years later.

I'm not much of a post-punk buff but from what I understand it started in the late 70s with bands like Siouxsie & the Banshees and Wire.

This is Siouxsie & the Banshees in '79:



That's pretty punk.

A couple of years later in '81:



Things are getting weirder and "post-ier" but the roots are still there, you can still smell the punk.

This is '77:



Again you can still smell the punk but it's definitely evolving, this is one of the less adventurous tracks on the album.

Somebody that actually knows post-punk well will be able to give better insight but I think at the most basic level post-punk bands were basically adventurous punks taking what they know about punk, their snarky vocals, their crinkly guitar tones, and their disdain for traditional rock and roll tropes and pushing the genre in more experimental directions from within. Fast forward 40 years and yeah the roots may not be as evident as they once were, but trace back the influences far enough and it all makes sense.