I believe the acceptable mold level in Michigan is 10x that of Ohio. Price is only one component, many people like a tightly regulated medical market to ensure safety.

If it were at a sufficient level for people to start getting sick you'd expect to see an increase in people with related issues, but you don't when you seek out news on this factoid, just a statement on the level being higher than in another place. Most products you consume will have at least some mold on them.

Or just turn it into an extraction, problem solved. Not many spores can survive a solvent wash, I don't know of any research that says they do.

Their metabolites might be left behind.

Or the tight regulation produces higher prices without any particular improvement to the product (e.g. taxi medallions). “tightly regulated” != “better”