Gandhi had the benefits of the English being war-weary after WW2 and the world being swept by a wave of anti-colonialism at the time. Quite often it actually ends well before the "you win" stage. The "Occupy Wall Street" people never really got further than step 1, for example.
Yes, it' definitely not a law of physics. It's an adage of value for a reason though too. It's about perserverance, if you can tolerate the previous steps indefinitely then there's a high probability you'll arrive at a later step.
I would say Occupy got at least to step 2 or 3 before they gave up.
I thought of a better example: Fidel Castro surely persevered right up until the end, but despite leading Cuba for almost 50 years it's a stretch to say he "won" in any significant way against the US.
