Yes. How can we help improve nutrient availability, generally?

From what I pointed out below, this salt processing seems to have underappreciated trade offs. But most importantly, the overarching picture of nutrient availability, not just for iodine, seems to have a bigger challenge at hand worth solving than simply using salt as a vehicle for one - which spirulina would help with in terms of protein and mercury / biotoxin removal, for example.

You fortify staple foods with nutrients. Such as SALT, bread, milk, etc.

The point is that you don't go looking for a new thing for people to consume to get them the nutrients they need, you fortify what they already eat.

Spirulina is not a good source of iodine anyway. Unlike kelp, which grows in iodine-rich ocean waters (and which is a decent source of iodine), spirulina is generally grown in alkaline inland lakes (read: iodine-depleted).