Of course one can go full quantum determinism. Yet free will is even more fragile than that. One only needs to pay attention to "attention" itself. Once one's threshold of attention span is sufficiently low one is indistinguishable from automata. Neurologic patients with bilateral pathologies in the hippocampus show this.
Once something is complex enough is indistinguishable from randomness or uniqueness. That's what happens with free will. It will lose its charm once we can handle the complexity it entails.
