We can replace Nylon with get this, poorer alternatives, if we gave a shit about the environment. I know it's unthinkable to switch to a worse product or user experience, but imagine caring more about the health of the planet.

This feels naive. For things like parachutes or airbags, I question whether you would actually have benefits from using something like cotton. In particular, they almost certainly do not perform at the same level. As such, you run the real risk of losing gains from other material to losses to maintenance.

Might be time to scale up spider silk synthesis, then?

Or maybe (high strength successors to) Rayon, which as I understand should decompose like regular cotton.

So, materiel that doesn't really exist?

And rayon doesn't exactly have a good history.

I'm all for looking for better things. Will be hard to replace some stuff, though.

Some people would just prefer that more people die from lack of effective parachutes or worse airbags if it means reducing the environmental devastation we wreak on the planet. Not sure if that is something you've considered.