Well the US isn't the entire world, the rest of the world doesn't really care how dysfunctional the US regulatory structure is. So either startups will route around this problem, they will grow based on non-US business until they can handle the regulatory cost, or they may survive in the state long enough to grow to handle any push back from the states. It certainly is an obstacle to growth, and innovation but progress already routes around the damaged parts of the system. Bitcoin will survive, however the US may simple lose its status as the "tech capital" when it comes to Bitcoin related enterprises.
I should point out I am not saying that is a forgone conclusion but the regulatory risk certainly doesn't help.
That concept "the rest of the world will save us" really doesn't seem to be working anymore. I think it's not working because most of the worlds governments/regulatory systems are as dysfunctional as the US system. I agree with your main point, Bitcoin will survive. Tech creations have a trendy, geeky, cool timeline. Bitcoin is very fashionable and edgy right now. Businesses that survive will need to base their business model of survival on real merits that are timeless because Bitcoin won't be cool and new forever. The US only has a partial hold on being the "tech capital" right now. The regulatory framework is killing more than just Bitcoin.