it would be very simple if you never exchange your coins, for dirty fiat money, even if they could track back you, address by address...
then how they can say that those addresses belong to you if you didn't use them to purchase anything and therefore your name does not appear to be connected with any of them? impossible
You need to convert your Bitcoin for dirty fiat money if you want to pay bills with your Bitcoin, and you can't do anything with your Bitcoin but small purchases that don't raise any alarms. You can't unfortunately buy a car or a house with Bitcoin and don't expect the IRS to knock on your door.
That's why a lot of people is holding. They don't know what to do with the BTC they make for example in here. They know they are limited to small purchases, or else you'll need to get it taxed..