It seems like you're nitpicking terminology but in case my original intent wasn't clear I'll try again. I'm saying that bitcoin has fatal flaws to work as a global currency at scale (I've estimated what that means) that aren't fatal flaws to work as a niche currency (it's present scale). So the answer to your original question is that surviving at it's present scale forever would not be surprising. Scaling and then revealing its flaws would indeed be fatal as there's no going back to being a niche once it scales and fails to work properly.