I can't imagine that the IRS would intervene with trying to monitor and track cryptocurrency. The volume of trading in the US is just a drop in the bucket compared to the stock exchange for fiat currency, and in order to properly monitor crypto users, there has to be implementation of standards and regulations on multiple different platforms. I can imagine that some of the bigger exchanges that operate to US customers would be targeted by the IRS, but that just means that those users would then migrate their trading elsewhere. I don't think any crypto exchanges want to give up their users' privacy, as that would be like them shooting themselves in the foot.
If I was the operator of an exchange, I would tell the IRS to fuck off, send a mass email to all my users informing them that the exchange was shutting down, so to make sure that they log in and withdraw their balances.
The good thing is that so far, Coinbase has pretty much told them to fuck off:
"[W]e strongly question whether the IRS has actually established a reasonable basis to support the mass production of records for half of a million people, the vast majority of whom appear to not be conducting the volume of transactions needed to report them to the IRS. Based on the information before us, this summons seems overly broad, extremely burdensome, and highly intrusive to a large population of individuals."
I hope they don't turn, but it sounds like they won't, because, as I said earlier, that will be the death of their own service.
Good luck, IRS, but there's no centralizing this decentralized market, no matter how hard you try. We will prevail
.... The internet has followed the same 
