3D-printing would be easier in some aspects - like repeat orders, being able to send impressions digitally, being able to undo any mistakes while trimming, guaranteed 100% translation between the trimmed impression and the final shell, etc. - but it also makes post-processing much, much more difficult. Jack told me one of the main reasons why they haven't been able to transition fully to 3D-printing is because it takes so long to buff out all of the print lines and imperfections. Plus, you'd be limited to a rather small range of colours. So, as always, everything has its pros and cons.
Like everyone here, I've never seen that happen to an Ares II cable. I have couple-year-old EA cables used in a multitude of environment that still look pretty good.
Yeah, PVC-based insulation stiffening up is pretty inevitable, but it does take quite a while if you take care of it, and by that I mean don't douse it in water and sweat on a daily basis. But, at the same time, almost all cable manufacturers use PVC-based insulation. One of the main reasons why is that even when it does stiffen up, it's still comparable ergonomically to alternative materials at their best.