Fresh water in massive quantites maybe. We have always rinsed our gear thoroughly in fresh water but zippers in things like thwart bags and dry suits seem to bind up after a couple of years. And my Tilley hat has corroded already. That might not get rinsed as much as needed.
I have trouble with wetsuit bootie zippers too, even when rinsed in fresh water . I think the advice was intended for gear with lots of nooks and crannies to trap salt crystals such as the inside of kayak ferruled paddles and zippers. Not larger stuff like sails and sailboats.
And anyone who has ferruled paddles might take note that an occasional vinegar wash will help. I wont do the vinegar thing after every paddle, but will do the fresh water rinse.