Depends where you are destined by your genes, but if you are destined to be NW6 or 7 then yes it is a binary situation, all else equal.
You are right that even finasteride is not always effective, but the odds are *very* bad to keep your hair if you genetically disposed to, and not using finasteride.
So, of course things can always be qualified by circumstances, propensities etc, but if we take those into account then even saying "the sun will rise tomorrow" is not okay because "it is not as simple as that". And taking all kinds of reservations and outlining all kinds of eventualities whenever we say anything will make communication difficult and incredibly cumbersome to get any point across.
In sum, for all intents and purposes, if someone is genetically destined to be high Norwood then yes, if they are not taking finasteride that is most likely exactly where they will end up.