Well, I agree with much you say here, but also note I mispoke. An additional vector for enforcement agencies exists: simply shutting down mechanisms that enable communications for such an exchange. Censorship is all it takes to end such an exchange.
While I'm aware of the inflationary tax on fiat, as you point out we can use it anonymously - and that's why I think the creation of Satoshi Nakamoto and BTC was done the way it was. I'd also point out that AXA is critically involved in BTC, and the company of the Chairman of the Bilderberg group. I am very skeptical of BTC for the same reasons I am skeptical of al Qaeda: I suspect it's a creation of the globalist intelligence community, rather than an organic defense against them.
However, that's not the point. The point I was making was that government cannot permit financial freedom without permitting it's own obsolescence. I doubt highly that will be permitted, although captive cryptocurrencies are ideal to eliminate anonymous transactions, and a pretense that they are secure and opposed by government exists that causes those parties government most wants to track the transactions of. There will come a time, I believe, when we'll be ordered to transact with BTC, or some official cryptocurrency.
We'll be left with only barter then to maintain anonymity. Crypto cannot by itself eliminate tyranny, but only by being part of a broad strategy of decentralization.