I agree that the fungibility-thing is one of the greatest threats to BTC (still potentially only afaik). But since they already inverted the burden of proof in tax matters in many countries from a long time, and given other regulations like civil asset seizures based on nothing (and already exceeding burglaries in value in the US: http://www.zerohedge.com/news/2015-11-17/police-civil-asset-forfeitures-exceed-value-all-burglaries-2014 ), they could as well start incriminating people for the mere use or possession of an anonymous/untrackable cryptocoin.

The only ways out for what I can see is either move/do business where this organized insanity is lacking, or go "system D" in the underground economy with all the risks involved. In any case there would be not much difference between BTC and say XMR in terms of user safety against TPTB.