Dude your hypothetical isn't for shit. You're baselessly asserting that the future is set. Then you ask me to imagine a scenario in the past and then tell me that I'm wrong because the future is set. Essentially you begin with your conclusion.
Now in a future that is not set, of course there could arise scenarios in which I will change my mind about the car for example I will smell some piss and I'll think about all the good times I had camping so I'll get a truck,because humans aren't machines, they are emotional beings,so fuck logic. Your assumption that the scenario will always play out the same way assumes that the algorithm used to arrive at a result is static, which isn't the case with humans, the algorithm may change due to emotional or environmental factors,you would be right in the case of computers -that they have no free will, but terribly wrong in the case of humans,.?...
Now in a future that is not set, of course there could arise scenarios in which I will change my mind about the car for example I will smell some piss and I'll think about all the good times I had camping so I'll get a truck,because humans aren't machines, they are emotional beings,so fuck logic. Your assumption that the scenario will always play out the same way assumes that the algorithm used to arrive at a result is static, which isn't the case with humans, the algorithm may change due to emotional or environmental factors,you would be right in the case of computers -that they have no free will, but terribly wrong in the case of humans,.?...