I grew up in the snow belt of PA. Your preaching to the choir...
When I made that comment, it was meant to imply the road salt corrodes the ball joint and that causes premature failure. I travel more miles in a year than most travel in five, and I run roads in almost every state, including my share of back/dirt roads and offroad.
I replaced my ball joints at around 150k, and they were still ok... but the pivots were rusted badly. I've replaced with greaseable Moogs, and (before switching greases) could pump a significant amount of water out of the lower joint each time they got serviced. I sit with 245k currently, an the Moogs have no play... but I also see zero water expelled now, which you can't do with a factory joint...