From my perspective, Paul is saying that if you are going to play someone else's game, your are obligated to follow their rules. In that sense, taxation isn't theft if you're using their currency to transact your business. Fortunately, none of use are obligated to play anyone's game. And, it is when God has a body of believers who see the game for what it is, and can not be made to play it, even at the expense of their own life, the "authorities that exist" will come to their end because their purpose will be fulfilled (see Rev. 12:10-12).