If the price of mycellium is dropping via scaling, subsidy and investment, then bans and legislation are not required. In fact, doing that will RAISE the price of fungus based solutions due to creating a non-competitive atmosphere between technologies. It not good news to hear of legislation protecting one technology from another, it's bad news.
Now if you had mentioned that in response the government is no longer protecting the oil industry, no longer subsidizing exploration, no longer using the military to protect oil fields, thus increasing the cost of plastics and exposing that technology to a true competitive market with fungus... then we would have something to cheer about.
My friends at Ecovative have been working on this tech for 2 decades. I am so happy to see their vision coming out in an article like this. I dont know who makes that "fleather" but thats pretty freaking cool.