I think the author goes a little too far here in equating the monetary value of salt with how valuable salt was. Salt had serious religious and mythological value. In nearly every single culture salt is said to ward off demons. Salt was used in courting rituals where new couples would process their love by licking the same salt rock. In some cultures, salt was part of the burial process. There isn’t a single salt production site in the world that isn’t named something like “salt place” or “place where the salt comes from.” Sure, the fact that salt was involved in all these traditions and rituals probably indicates that salt was generally available to most people, but clearly it was still very important to them.

If you’re wondering why salt was so mythologically important, just go over to your counter, put some salt in your hand, lick it, and try to imagine how you’d describe the taste to someone who’s never tasted it before. You can’t. Salt is its own thing and there’s nothing else like it.