Definitely a good thing to keep in mind. Doing a bit of further research, depending on the composition of the tinsel wire, it’s seems feasible to DIY a cable with soldered connections to 3.5mm male plugs, albeit with some extra material spent as practice to get technique, temperature, and time correct.
Unless I happen to find a premade cable that is suitable for conversion out of old hardware, it definitely seems like actually sourcing woven tinsel wire in suitable thickness for a headphone cable is quite the challenge (for a reasonable price anyway).
If nothing else, the Syncwire cable is cheap enough to be a good value, provided it does last a while.
Just to do a bit of sanity checking on my end and because I still have the dead KabelDirekt cable for reference, I chopped and dissected the cable for speculation. I am first shocked at how good of reviews such a cable can get for its construction choices. The outer ground is of good size, but both stereo channels use tiny 26 or 28 awg 10-strand copper, which is no wonder the thing failed in under a year. Everything in the cable appears to be regular stranded copper. The PVC sheath on this cable is about 4mm, same as the (presumably pvc sheath plus) braided Syncwire cable. KabelDirekt’s comparable braided cable is about 5mm by comparison. The review distribution between the PVC KabelDirekt and Syncwire cables are nearly the same, which makes me wonder how bad a cable really has to be for the reviews to significantly dip.