I'm taller than the first, have more teeth than the second. And of.course my banjo is strung with galvanized wire from Home Depot. In all seriousness to the OP, could the fraying be due to Stress Corrosion Cracking caused by chlorides in the water we sail in reacting with the stainless wire?
There are a number of likely factors that cause standing rigging to degrade and fail - corrosion, cyclical stress (constant load and unload cycles), shock stress (from a high-wind gybe for example), damaged strands (from kinking or abrasion), coiling the wire too tighyly, or simply overloading the shroud. In my experience, most Hobie sailors tend to be pretty rough on their sranding rigging.
An interesting thing I found when looking into having larger diameter shrouds made by some different manufacturers (APS & Loos Co.), none of those manufacturers recommeded (or offered) coated shrouds because the coating allows salt water to be trapped against the shrouds which accelerates corrosion and also makes inspection impossible.