Keep in mind that the problems aren't just having saltwater splash out onto softer stones, but also having fast enough evaporation and not having summer rains dilute the water. It's the combination of splash-out and evaporation that leads to salt recrystallization pressure that puts stress on softer stone. This is probably why more problems are seen in dry and hot Texas compared to wet Florida, for example. The local stones used also matter and some builders use materials that would be a problem for a non-salt pool as well, though it may take longer to notice in such a pool.