In the past, salt was a valuable resource that was necessary for storing food and flavor; a valuable resource that many civilizations fought over. How come people just didn’t try evaporating sea water to get salt and instead go to entire wars for?
u/Lynx_Rufus addresses in this answer the difficulties of making salt. There's also a comment to his response further down that notes how much sea water you have to boil to get usable quantities of salt (spoiler alert: a lot).