Keep in mind that cables fail due to physical conditions, i.e. the tight bending radii that every manufacturer's brifters inherently have. It isn't a friction issue causing the problem, so lubricants or coverings aren't going to significantly mitigate the issue. I am not a materials engineer so I can't comment on what other SS alloys might be an option for a better quality cable. There may also be composites that could work for all I know. I do suspect though that alternative materials would cost more money and would have to have a much longer life to be cost effective vs replacing an inexpensive cable once a year. Probably the only real solution would be a radical redesign of the actuation methods that would result in less bending stress on the cable.
John