On the government outlawing Bitcoin they havent had a good track record on stopping people from drinking alcohol during prohibition and effectively lost the war on drugs. If people want something, its in their nature to find a way to get it. Paraphrasing Princess Leia. . . the more the governments tighten their grasp, the more plebs that slip through their fingers. Confidence in governments has eroded over time, and their currencies the same. While still on the fringe, people have been using alternative transferrable value for a long time in the form of phone minutes, gift cards, cigarettes. A CBDC currency wont reduce that any more than digital dollars have. As long as people can have physical goods and meet in person or communicate privately they will be able to perform commerce out of band of government control whether its legal or not.