Really good points, and to add my thoughts on what divinemsm said: I am of the Yoda school of thought: "Always in motion is the future". If you get the 'underlying factors' right, and 'the past', meaning where this situation started, the 'future or outcome' card has a chance of being right. But don't judge your worth as a reader on that because stuff happens.
Back to the querent's thesis: do the cards reflect an ending that can be changed via free will or can they read fixeddestiny. A typically vague reply: some of each. While it is true that we always have choices, our personality or a situation makes some choices so unpalatable that some endings are pretty well inevitable.
Alta