There is absolutely nothing that would prevent a government outlawing and criminalizing bitcoin at any point in time. With one stroke of a pen government can outlaw owning bitcoins or performing any transactions in bitcoins. I'd say this is bound to happen eventually with certainty because no government would be willing to lose control on currency (especially ability to pull it out of thin air) and thereby the power they exert on economy as well as other nations. You can count on this. So all those scenarios you mentioned are meaningless because any capital you have in bitcoins is bound to evaporate overnight and reduced to zero at the whim of the government.

See: https://en.wikipedia.org/wiki/Virtual_currency_law_in_the_Un...

Congress may have the power to prohibit virtual currencies (VCs) under its power “[t]o regulate Commerce with foreign Nations, and among the several States”[64] and under its exclusive constitutional power “to coin Money” and “regulate the Value thereof.”[64] In a November 2014 decision, the Court upheld the power of regulators to prosecute a defendant who “designed, created and minted coins called ‘Liberty Dollars,’ coins ‘in resemblance or in similitude’ [or made to look like] of U.S. coins."[65] Although the defendant did not pass the Liberty Dollars currency as a counterfeit, the currency were in close enough “resemblance of coins of the United States or of foreign countries” and consequentially fell under the authority of 18 U.S.C.A. § 486.123 The Court has not decided if § 486 includes the power to prohibit VCs, but if a Court decides that the purpose and intent of VC resembles United States or foreign currency it may fall under § 486. The Stamp Payment Act of 1862 prohibits anyone from “mak[ing], issu[ing], circulat[ing], or pay[ing] out any note, check, memorandum, token, or other obligation for a less sum than $1, intended to circulate as money or to be received or used in lieu of lawful money of the United States.”[66] The Court has not decided if Congress has the power to prohibit VCs under this Act or any other existing regulation or statute.