The question basically amounts to asking is it possible a government will do something insanely stupid in the future.  Yes, of course it is.

However, all the indicators seem to be that the move is toward regulation and not prohibition.  I think what is much more likely is that there will, at some point, be some incredibly burdensome and ill considered regulation that harms the market.  Since the feds, remarkably, seem to be behaving more or less rationally, I think this is most likely to come from the states.  For some reason, my crystal ball has some crusading New York State (or possibly California or New Jersey) prosecutor taking some ludicrous position on Bitcoin.  (Of course, the current Florida prosecution could be the thin edge of the wedge.)  Just call it a hunch.