I doubt that it will go way that far. Worst thing would be that some people will be discouraged to exchange it to FIAT and the others might still be doing it as usual. It is pretty simple to avoid it anyway because people could do a peer-2-peer exchange without involving any exchanger thus this could be use to avoid the huge tax when you are exchanging it to FIAT
Governments will attack bitcoins in the future and that is for sure. Governments are very intelligent and criminal minded people they will only look at their profits so they are waiting for bitcoin to grow so once the bitcoin grows and reaches to the stable price they will definitely attack the bitcoin.
Care to elaborate more about what you meant by "attack". Thoughts I have addressed this but the worst they could do will be to either bann
BTC or put on a high tax for the BTC/FIAT exchanger to discourage people.
Banning
BTC will never be a succesful way for them to "attack"
BTC because eventually it will just lead
BTC deeper underground. Most people will still use it eventhough it has been bann i.e russia