Why were these ropes never released? I understood that Kevin He/Erik Cassel was working on them, but why wouldn’t someone continue on them/make them from scratch again?

They’d be really really useful in a lot of things, especially since hinges suck:

They were a buggy mess. I was able to play around with them at the BA Maker Faire since one of the computers had the articulated physics build on it. You couldn’t do anything cool with them because they’d just explode.

Also as cool as they would be I don’t think there’s huge demand. I mean what would anyone use ropes for? Bridges, balloons, swings, and… that’s about it. Even if we got them they’d be plagued with distributed physics so you wouldn’t be able to seriously use them in your game. You’re much better off scripting your own ropes that do what you want them to do.