The reality here is that this govt agency is running with very restricted and limited budget and is using technology to try and find unpaid taxes rather than humans.  The days of human audits are long gone.  Now it is about automating tax collection, and if you though that crypto was some way to stick it to the man, wrong.  You have walked into the automated jail of the IRS.  Yes, you will be identified - only because your blockchain transactions and their fingerprints can be logged and identified using their AI, just like facial recognition, Geolocation, etc.  

If you think this is bad, try and be a US citizen and have overseas assets and not report them on FBAR or FATCA forms.  The penalties are so severe that it makes the fines from human audits look amateur.  When you have big computers and minimum labor, you can make up your budget shortfall with $10K+ fines (year on year), plus interest plus penalties, etc.  It doesn't take long before the money you've collected in penalties makes the actual taxes that law abiding citizens paying look like chicken feed.

So know your adversary.  If you didn't get a letter, that's great.  You were not yet identified in the first wave.  But the IRS can scan a blockchain just like anyone else can and they have more people & machines than you can imagine.  This is what happens when organizations want to do more with less - they favor AI over humans.  The IRS is no different.

Pay your taxes and keep good records.  It is far cheaper that way.