Regarding KYC and OPSEC: Bitcoin fixes nothing if we're all in prison and the masses agree we should be. There are two possible ways forward: Very fast education of at least a large minority of the people and/or a majority of the law writing class that bitcoin does not equal crime, or the widespread use of extremely good privacy tools and practices. I believe a failure of both of these is the biggest threat to Bitcoin's future.

And for the "go to El Salvador" solution: It won't be a prosperous place if it's cut off from all international trade, regardless of its internal freedom of BTC usage etc.