Let's not discuss this outcome because it is completely infeasible unless you have one world government. If you want to discuss what would happen if the US banned it, then I think we have a reasonable thought experiment of something that could potentially happen (I don't think it is a likelihood, but it's not a non zero chance). In a US ban scenario, most holders would comply immediately, a small portion of holders would leave the US and everyone in between would be left to fight through the courts, legislatures and in the streets to have at least a few states be Bitcoin states. I do think it is important to work to plant the seeds for this now amongst pro bitcoin states and get them to entrench the right to bitcoin ownership and transactability into law.