You can't guarantee or even approximate a given input and output for a scenario like this.
But we also don't need to specify initial conditions exactly to do science.
I'm less convinced that the equations themselves are unknowable.
Politicians will screw up the implementation, businesses will engineer around it and the alternative solution might ultimately come out to be a better one in practice than in theory.
Trying to define economics by simple equations which you expect to define policy is a lost cause.