The net bags would allow the spores to fall from the mushrooms to the ground where a solid bag would not. But there is more needed to get the mushrooms to grow.
The actual fungus grows in the ground thru out the year and only "fruits" and develops a mushroom when the conditions are right. The mushroom does release the spores that spread the mushroom and they develop in the folds of the main body.
The fungus part is thought to have a symbiotic relationship with roots of trees and needs the tree to develop. I have best luck around sycamore, ash, poplar, catalpa, elm, apple, and oaks. They are usually found in loose fertile soil with leafy cover. Too much leaf cover and the mushroom does not break thru and they are hard to find.
If one could grow them commercially, it would be a great accomplishment. But for the most part, it seems like they will always be a "wild" product.